1A would be (if 2)
2B won (if2)
3C is polluted ( if 1)
4C had driven (if 3)
5B had slept (if 3)
6D would have said (if 3)
7A is/can enjoy (now)
8B smoked
9B unless you work harder
10C had Peter left (if 3, đảo ngữ :had +s+v3/ed0
11D wouldn't have been (if 3)
12C knew
13A if he had missed it, he would have been late for his interview
14D if he hadn't stepped on the mine, it wouldn't have exploded.
15C if i knew Philosophy, I would be able to answer your question.
16D if I hadn't been ill, I wouldn't have been absent from school yesterday.
17C if his car were not broken, Peter could go out for lunch.
18A have(if 1)
19D were(if 2)
