1 may have 2 would 3 must not 4 can’t 5 must have climbed up the tree 6 might have met somewhere before 7 can’t have told me a lie 8 There used to be a lot of trees 9 my friend had to apologize to the professor10 Will you pass me the stapler 11 had better not miss the start of 12 They can’t have gone on a picnic 13 You should have arrived earlier 14 You will be able to earn money 15 He would[used to] wash his puppies 16 We don’t have to worry about[We needn’t worry about, We don’t need to worry about] 17 suggested that we (should) walk down Broadway and visit Times Square 18 ③19 ② 20 ⑤ 21 changed → (should) change 22 I’m used to → I used to 23 should rather → would rather 또는 should 24 should → shouldn’t 25 must → must not26 needs not → need not 또는 doesn’t need to 27 may must → may have to 또는 may[must] 28 found → find29 ① 30 ④ 입니다 감사합니다