Question

if clauses type-1; type-2; type-3 ​

Answer 1

Explanation:

1) the main clause uses will ,can ,may or might +the base form of a main verb

2)the tense in the if clause is in the simple past and the tense in the main clause is in the present condition or the continuous condition that thing would be happen in all conditions in the sentences are not fixed

3)used to express the past or impossible situations that can no longer been changed