8.31 possible situations

When you are talking about a possible situation in the present, you usually use the simple present tense or the present perfect tensein the conditional clause. In the main clause you usually use a modal.

• If anyone doubts the truth of this, they should look at the two most successful post-war economies, Germany and Japan.
• Unless you've tried it, you can't imagine how pleasant it is.

'If'-clauses of this kind can be used when you are offering to do something, or giving permission for something to be done. You use a modal in the main clause, and the subordinate clause consists of 'if', a pronoun, and 'want', 'like', or 'wish'.

• I'll teach you, if you want.
• You can leave if you like.