Ответ:
1.You (will not be able)… to pass the test tomorrow if you don’t work hard today.
2.They .should.. pay more attention to their studies.
3.John .should.. work hard to get the scholarship.
4.My friend .should.. think about his future job now.
5..Would ..you like another cup of tea? — Yes, please.
6..Should..I do this exercise in writing? — No, you (need not)…; you ..must. do it orally.
7.Excuse me, ..could. you tell me the time, please?
8.Students …must come in time for the lessons.
9.I ..will have to. revise the rules once more, as I haven’t passed the exam.
10.I ..should have followed. your advice.
11.He .couuld.. swim when he was three years old.
12.You … open the window. It’s rather hot in the room.