The weather in Beijing is colder than that in Nanjing.

1. Choose sentence B as a comparative level, and pay attention to the fact that the objects to be compared must be consistent before and after. From the topic, the weather should be compared with the weather, not with the city. Therefore, in the above article, demonstrative pronouns must be used instead of weather. In addition, this is also to avoid duplication. Because the weather in Beijing is colder than that in Nanjing, please write it down completely. (yes.

2. choose the b object clause. The leading words don't have this and these, so they are directly excluded. Judging from the meaning of the question, the clause part itself is a declarative sentence, which leads to the second usage of that.

On the object clause: several problems that should be paid attention to in the object clause;

1. Word order: it must be the word order of a declarative sentence. However, it should be noted that what's wrong/the matter/after to you and other sentences seem to question the word order, but in fact they are statements.

2. About words with sounds:

If the clause itself is a declarative sentence, use a declarative sentence.

If the clause itself is a general question, use if or where. When there is .. or not at the end of the sentence, you can only use where.

If the clause itself is a special question, use your own special question.

3. About tenses

The main clause is the present tense, and the clauses are unrestricted, so you should use everything. The main clause is the general past tense, and the clauses use one of the corresponding past tenses. Note: When clauses express objective truth and eternal laws, they use the simple present tense regardless of the tense of the main clause.