What's the difference between if and weather in usage?

The difference and usage between if and the;

1, if as a subordinate conjunction, leads the conditional adverbial clause, indicating "if". Pay special attention to the if-guided conditional adverbial clause using the simple present tense and the main clause using the simple future tense, that is, "the Lord follows the present."

If it doesn't rain tomorrow, we will have a picnic.

If it doesn't rain tomorrow, we will have a picnic.

2. if/when can lead an object clause to indicate "whether". The leading word has practical significance (whether or not) in the clause, but it does not constitute any component, so it cannot be omitted. It is an uncertain tone transformed from general interrogative sentences.

If usage

As subordinate conjunctions, 1 and if can guide conditional adverbial clauses, adverbial clauses and noun clauses.

2.if leads to conditional adverbial clauses, which can be real or imaginary.

3.if-guided conditional clauses can omit be and subject.

4.if-guided conditional clauses are sometimes followed only by emphasis, indicating that the speaker is very eager for someone's conditions to be realized.

5.if can lead the adverbial clause to make a solution of "although, even if", often used with even.

6.if can guide noun clauses and make a "whether" solution, which is often placed after verbs such as ask, doubt, know, learn, see and think. Generally used in spoken language, not at the beginning of a sentence.