English Grammar Test: Conditionals (Practice Test 2)

This is a zero conditional: a fact about how something always works, with the present simple in both parts. Would start would need a past verb in the if-clause.

In a first conditional, the if-clause uses the present simple even for the future: If it rains. Will rain after if is a common mistake.

A second conditional talks about an unreal present: If + past simple, would + verb. So the answer is had.

The main clause has would do, so the if-clause takes the past simple: found. Had found would need would have done.

The third conditional is about an unreal past: If + past perfect, would have + past participle. We did not leave early, so we did not catch the train.

The main clause wouldn't have gotten shows a third conditional, so the if-clause needs the past perfect: had taken.

Unless already means "if not", so the verb stays positive: Unless you study = If you don't study. Adding don't makes a double negative.

This is a mixed conditional: a past condition (had gone) with a present result (now), so use would + verb. Wouldn't have been would talk about the past, not about now.

The second conditional uses if + past simple and would + verb for an unreal present: lived ... would visit. The others are zero, first and third conditionals.

Should you need is a formal way of saying If you need. Had and Were can also replace if, but only with a past participle or to-infinitive, not with need.