Present perfect
1.You(ever visit) ....................Mexico?
2.I(know)...............Alex since he (be)..................a child
3.What you (learn).....................since you (come)..................here?
4.In the last fifty years,medical scientists(make)..................many important discoveries
5.Sice classes(bigin)................,I(not have )..................much free time
6.I(write)......................my wife a letter every day for the last two weeks
7.You(buy).................a ticker yet?
8.We(just come).......................bsck from our holiday
9.You ought to wash the car.You(not wash)...........................it for ages
10.How long Trevor and Laura(be)................married?
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