used for the present hypothetical. If they had been there, I would have been happy. If I had stayed , I would have met her. For future hypotheticals we use the simple present . This is not actually surprising, since the simple present is used for near-future events in a variety of contexts in English. If they come, I'll be happy. Note, however, that it's actually possible to use both the modal will and other future constructions such as going to in this construction, depending on context. If they will reduce the price, I'll buy. Here will retains some of its historical sense of willingness as opposed to indicating mere futurity. If they are going to leave, then I am, too. This is a pure future conditional. You can use going to for the future hypothetical in almost any case where you would otherwise use the simple present with no change in meaning. Thanks, Sorry I was meaning to say "past perfect" not "present past". And my question was asking about an explanation why they make sense, can you help with that? -- Louis Rhys Apr 4 '11 at 16:12 @Louis, I thought I had helped with that. To be clearer: the present conditional uses the subjunctive , which is similar to the past for historical reasons. The past conditional uses the past perfect in order to avoid similarity to the subjunctive. And the future conditional uses the present tense because the present tense is often used for future actions