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Câu1 The last time I saw him was in 2015

=>I haven't....................................

Câu2 Don't throw trash in the park or you will make this area dirty.

=>If you.........................................

Câu3 The last time they visited Europe was two years ago.

=>They haven't.......................for two years.

Câu3 In the future, the car can run on water.

=>The car of the future will........................