6 Has - tried
7 Did - go
8 have - been
9 have travelled
10 have been
11 Have - finished
12 came - tell (vì mệnh đề trần thuật đằng sau giữ nguyên ở hiện tại đơn chứ không lùi thì)
13 have visited - went - was - haven't visited
14 did - come
15 came
16 did - watch
17 have - left
18 have - known
19 met - have known
20 happened





