Respostas
Eu também não entendi de primeira, então dei uma pesquisada:
Conditionals describe the result of a certain condition. The if clause tells you the condition (If you study hard) and the main clause tells you the result (you will pass your exams). The order of the clauses does not change the meaning.
If you study hard, you will pass your exams.
You will pass your exams if you study hard.
First conditional
We use the first conditional when we talk about future situations we believe are real or possible.
If it doesn't rain tomorrow, we'll go to the beach.
Arsenal will be top of the league if they win.
When I finish work, I'll call you.
In first conditional sentences, the structure is usually: if/when + present simple >> will + infinitive.
Então:
1. a) if we go out tonight, we'll go to that amazing restaurant.
b) If you don't tell me truth, I'll not help you.
espero ter ajudado. :)