Winter vacation homework in Grade 8 in 2020 (Mathematics, Geography, Biology)

Winter vacation homework, Grade 8, 2020 Answer: Mathematical Answer.

Page 1~3

I. Calculation

1, solution: Because triangle ACF is equal to triangle DBE. So AD-BC = DC- BC. That is AB=CD.

Because AB+CD+BC=AD, AB=( 1 1-7)÷2=2.

2. Solution: Let ∠BEF and ∠FEM be x, then ∠CEN and ∠NEM are 2X, so.

X+X+2X+2X= 180, so ∠ FEM+∠ nem = ∠ fen; 6X= 180, so ∠FEN=30+60=90X=30.

fill (up) a vacancy

A when the inverse of 1~82 is plus or minus 7.

Third, ellipsis

Four. Ab v. solution (draw it yourself)

Page 4~6

I. CDAD II. Company two. Three. Four. Intravenous injection.

Seven out of six. Solution: 2X-3 2X-2=-X+3 1 and 2x+x = 8x = 5x = 15.

Page 7~9

One, slightly two, dad three, four, slightly.

Verb (abbreviation of verb) 1, solution: 20-y =-1.5y-2-2.5y =-22y = 44, take 5.

2. Solution: 7X+6X-6=20 13X=26X=2.

3. Solution: 8x-9x-6 = 6-x =12x =-12.

6. Triangle: 100×4=400 (block) Flower arrangement: 50÷0.5= 100 (block)

7. 1 company 22, company 43, company 54 15, company 3 (left 1 to 5, right 1 to 5) Don't get confused.

Page 10~ 12

1. 1 502, solution: because ∠BAC+∠B+∠C= 180, ∠ BAC =180-30-40 =1.

Second, ellipsis

Third, they all rotate 90 degrees clockwise.

Four. -1 brought in by -2ab

Five, because the triangle ABC is equal to the triangle DEF, DF=AC=35kg.

Sixth, ellipsis

Seven, π x 2h = 2π x 3+3π x 2h π x 2-3π x 2 = 2π x 3h-3 = 2π x 3h = 5π x 3.

Page 13~ 15

I. omission

Second, BACD

Third, draw an angular bisector with a ruler and mark it with a scale.

4. 1，25 B-(b-5)= 2925 b-b+5 = 2924 b = 24b = 1。

2、9y-3- 12 = 10y- 14-y = 1y =- 1

3, =-X+2X squared +5+4X squared -3-6x =-7x+6x 2+2.

4.=3a squared -ab+7+4a squared -2ab-7=7a squared -3ab.

Verb (abbreviation of verb) solution: Because all triangles ABC are equal to triangle ADE, ∠D=∠B=25.

Because ∠EAD+∠D+∠E= 180, ∠ EAD =180-25-105 = 50.

Page 16~ 18

1. 1, c because there are countless symmetry axes 2, c because the broken line of c is parallel to the broken line of a.

Second, ellipsis

Three. Canada

4. 1，=-X+2X-2-3X-5=-2X-72，=5a+4c+7b+5c-3b-6a=-a+9c+4b。

Page 18 2. Choose B.

Page 19~2 1

I. 1 and 2 Article 2. Relationship: Y=8X+0.4X Price: 8×2.5+0.4×2.5=2 1.

Two. AB three. B.C.

4. Take the Y-axis as the central axis to be the symmetrical point of point A and point B, and then connect A 1 with B, and B 1 with A, and the intersection point is point P..

V =8XY-X square +Y square -X square +Y square -8XY=-2X square +2Y square.

Extracurricular development 2,2× 4-2× 2× 0.5× 2 = 8-4 = 4.

Page 22~24

I. 8 10076

Second, I don't understand three, (1)Y= 10X+30(2) pair, because it is a straight line that does not pass through the origin.

Verb (abbreviation of verb) a1(4,0) e1(10) b1(4,3) d1(1,3).

Page 25-27 I, (-3,2) (-3,2) (3,2 2) II, page 26 III, ADBDB

Fourth, because ∠ Abd > ∠CBD，∠ADB & gt； ∠CDB，so a b+ AD & gt； BC+CD V， 1，AD=AB+BD=AC+CD=AB+BC+CD2，AB=AD-BD=AC-BC=AD-BC-CD3，BC+CD=AD-AB4，BD-CD=BC。

Extracurricular development

1 、( 1) 1、2、3、4、5(2)Y=n(3) 100

Page 28~30

I. 1, 62, 8

Second, =-x+5+4x+5x-4+2x2 = x2+9x-1third, BDCDDB.

Fourth, the solution: be = de =1.7cm.

Extracurricular development

2,3 minutes = 180 seconds They met five times.

Winter vacation homework, Grade 8, 2020 Answer: Geographical Answer

chapter one

I. Multiple choice questions

1.A2.B3.C4.C5.A6.B7.C8.D

Second, fill in the blanks

1. People's Republic of China (PRC); Beijing II. East; North; Asia; Taiping 3.960; Russia; Canada; 34.VIII Beijing 5.18000; Taiwan Province Province; Bohai sea; Yellow sea; East China Sea; South China Sea; Taiping 6.12.95; 2 1.2%

7. The population base is large and the growth rate is fast. Economy, environment and resources; family planning

Third, read the picture analysis questions

1, (1) Heilongjiang; Black dragon; South; Zengmu reef

(2) Heilongjiang; Ussuri River; pamir

(3)5500

2.( 1) Xizang Autonomous Region; Hide; Lhasa b Guangdong province; Guangdong; Guangzhou c Heilongjiang province; Black; Harbin d Gansu province; Gan; Lanzhou (2) a; B

3.②A Inner Mongolia B Ningxia Hui nationality C Xinjiang Uygur nationality D Tibet E Guangxi Zhuang nationality

(3)① Shaanxi ② Shanxi ③ Hebei ④ Shandong ⑤ Anhui ⑤ Hubei.

④ ⑦ Bohai Sea ⑧ Yellow Sea ⑨ East China Sea ⑩ South China Sea.

(5) Yunnan Province; Guangxi Zhuang Autonomous Region; Guangdong province; Taiwan Province Province

(6) Heilongjiang Province; Xinjiang Uygur Autonomous Region (7) Hainan Province; Haikou; Joan; majority

Fourth, the connection problem.

Korean nationality-long drum; Mongolian-Ma Touqin; Kazakh-Dombrat; Zhuang nationality-acacia flute

chapter two

I. Multiple choice questions

1.A2.C3.C4.D5.A6.A7.A8.B

Second, fill in the blanks

1. Himalayas; Mount Everest; Nepal; 88482. Tibet; Loess; Inner Mongolia. Tarim; Taklimakan; Qaidam; Qinghai-Tibet 4 Northeast China; Sanjiang; Songnen; Liaohe River; Middle and lower reaches of the Yangtze River. Summer and autumn; Small; Big six. Taiwan Province Province; Burning flame; Turpan 7.0℃; 800; Warm temperatures; *; Humidity; Semi-humid 8. West; East; Quiet and peaceful

Third, read the picture analysis questions

1, (1)① Yinshan ② Daxinganling ③ Qinling ④ Nanling ⑤ Hengduan Mountain ⑧ Himalayan Mountain ⑧ Qilian Mountain ⑨ Changbai Mountain ⑩ Taiwan Province Mountain.

(2) Xinjiang Uygur Autonomous Region; Tarim basin; Hebei province; Shanxi Plateau; Fujian province; Northeast-southwest; Plain in the middle and lower reaches of the Yangtze River; Sichuan Basin

(3)① Tianshan Mountain and Yinshan Mountain; (2) Kunlun Mountain and Qinling Mountain; ③ Nanling Mountains; ① Daxinganling, Taihang Mountain, Wushan and Xuefeng Mountain; ② Changbai Mountain and Wuyi Mountain; ③ Mountains in Taiwan Province Province.

(4)

(1) Daxinganling; Bayan Kara; Summer; Nonmonotone

(2) Pacific Ocean; East (3) southwest (4) waterlogging; dry

(1)① Bayan Kara ② Bohai Sea

(2) Estuary and Old Jin Meng; 7; 8(3) soil erosion; Build a dam

Fourth, short answer questions

1. A: The trunk and branch of the Yangtze River have a circulation mileage of more than 70,000 kilometers, and the freight volume accounts for 60% of the national inland river freight volume.

2. A: Complex and diverse; The monsoon climate is remarkable; What other weather is it?

chapter three

I. Multiple choice questions

1.D2

Second, fill in the blanks

1. climate; Land; Water; Ocean; Biology; Mineral 2. The total amount is large; Subtract 3 per capita. More people and less land; Cherish and make rational use of every inch of land. 4. There are many in the south and few in the north; Less things; Mostly in summer and autumn; Less in winter and spring; Great international changes. Inter-basin water transfer; Building a reservoir; Scientific water use; Save water (protect water resources and prevent water pollution) 6. Biology; Minerals; chemistry

Third, read the picture analysis questions

1, (1)A Northeast Forest Area B Southwest Forest Area C Southeast Forest Area (3) North China and Northwest China

2.( 1)A Diversion from Luanhe River to Green B Diversion from Yellow River to Green (2) Yangtze River Basin; North China; northwest area

(3) the Yangtze River; Beijing-Hangzhou; Three Gorges; Danjiangkou; Zhengzhou; Shijiazhuang; Yangtze river; Jinsha; northwest

(4) Yangtze River, Huaihe River, Yellow River and Haihe River; Four horizontal and three vertical, north-south deployment, east-west mutual assistance

3.(2) Relatively concentrated; Nonferrous metals (3)12; Beauty; Russia; 20

(4) rare earth; Molybdenum; Coal; Mercury; Zinc; bauxite

Fourth, short answer questions

1, a: Cultivated land is mainly distributed in plains and basins in the eastern monsoon region; Woodland is mainly distributed in the mountainous areas of northeast, southwest and southeast; Grassland is mainly distributed in eastern Inner Mongolia and the eastern and southern parts of Qinghai-Tibet Plateau.

2. A: Four kinds of seafood: large yellow croaker, small yellow croaker, hairtail and squid; Four major fishing grounds: Huangbohai Fishing Ground, Zhoushan Fishing Ground, South China Sea Coastal Fishing Ground and Beibu Gulf Fishing Ground; To protect the "blue land", it is necessary to implement the comprehensive management of marine resources, improve the law enforcement of marine environmental protection, and promote the sustainable utilization of marine resources with high technology.

chapter four

I. Multiple choice questions

1.B2

Second, fill in the blanks

1. Daxinganling; Helan Mountain II. Qinling mountains; 0℃3. Northwest; Qinghai-Tibet 4 Ice; Big five. Roof of the world; Cold 6. Yellow river; Haihe 7. Shanxi; Shanghai-Nanjing-Hangzhou; Pearl River Delta. Hoh Xil 9. Drought; 200; Hetao; Yinchuan

Third, read the picture analysis questions

1, (1)A north b south c Qinghai-Tibet d northwest (2) Qinling Huaihe River; 800; 0℃

(3) Plateau; 4000 meters (4) climate (5) plateau agriculture; Oasis agriculture

(6) one, two; Kunlun; (7) Hengduan section of Tarim River; Taklimakan Ma Kan

2.( 1)① Daxinganling ② Altai Mountain ③ Tianshan Mountain ④ Kunlun Mountain ⑥ Altun Mountain ⑥ Qilian Mountain ⑥ Yinshan Mountain (2)A Junggar Basin B Tarim Basin C Inner Mongolia Plateau D Qaidam Basin (3) 4; The land is vast and sparsely populated (5) milk; Hair; Hami melon; grape

3.( 1) 1 (2) Qinghai; Yangtze river; Yellow river; c； B(3) Himalayas; Indian Ocean; Mount Everest (4) Xizang Autonomous Region; Qinghai province; Sichuan province; 1%(5) yak; Tibetan sheep; Tibetan goat (6) Qinghai-Tibet; Xining; Golmud; Kunlun mountain pass; Tuotuo River; Amdo; Naqu; Dangxiong; Lhasa; Altitude; (7) The route and longest mileage of Qaidam crossing frozen soil; Oil; Asbestos, rare metals

Winter vacation homework, Grade 8, 2020 Answer: Biological Answer

First, multiple choice questions

1-5 babcd 6- 10 bbccd 1 1- 15 daadc 16-20 badcc

2 1-25

Second, fill in the blanks with pictures.

26.( 1) 1 articular fossa 3

(2) Articular cartilage

(3)4 joint capsules

27, (1) head, chest, abdominal exoskeleton segmentation.

⑵D

28, cell membrane, cytoplasm, nucleus, cell wall unicellular fungi and multicellular fungi.

29.( 1) First, you can get food by swimming to defend against the enemy; Second, you can breathe in the water.

(2) Killing/poaching breast-feeding people (meaning similar)

(3) The fuselage is streamlined, which is beneficial to reduce the flight resistance; Forelimbs become wings; Short digestive tract, rapid excretion of feces, which is beneficial to lose weight during flight; Double breathing; Heart 4 cavities; The pectoral muscles are developed with keel processes; The bone is thin and light, and the long bone is hollow; Large appetite and fast digestion provide a lot of energy for flight. (If you answer any 2 points correctly, you will get extra points.)

30 、( 1)B(2)F(3)C(4)A(5)E(6)D

3 1 、( 1)D

(2) Sterilize/kill other miscellaneous bacteria outside the experiment (agreed).

(3) Inoculation (4) and control (5) B.

4 1, (1)4(2) Grass-herbivorous insect-frog-snake-eagle (3) Competition (4) Grass (5) decomposer.

42.( 1) Eyepiece objective (2) thin spiral (3) mirror concave surface

43.( 1) Pollen of ovule anther in ovary of pistil 6.

44.( 1) Party A turns left and Party B turns right. (2) Avoid harmful stimuli and favor favorable stimuli. (3) reaction.

45, organic oxygen carbon dioxide carbon oxygen

46.( 1) Oxygen and carbon dioxide (2) Breathing (3)

47. (1) No.2 (2) The students blocked the outside light. (3) The covering operation did not completely unfold the epidermis.

48.( 1) Water has the greatest influence on seed germination. (2) Seeds can germinate, but air is a necessary condition for seeds to germinate. (3) The number of seeds is too small, which is very accidental. (4) Replace it with 10 seed.

49. (1)B mice died of hypoxia. (2) Both plants and A mice consume oxygen when breathing.

(3) Not suitable. Will compete with people for oxygen in the room.