下列句子中各有一处错误，找出并改正（英语）

Question

1.I have bought the piano for six years ____2.---where have you gone?---I've gone to school ____3.how many pages have you read by the end oflast year _____4.while i walked in the street,I saw my teacher ______5.They have had their lunch at twelve ____6.The workers have repaired the machines just now ____7.You have waited here since tow hours ______

Answer 1

1.这里的bought是短暂性动词，所以应该用持续性动词替换才符合for six years，可以改成 had,owned,kept之类的 2.gone-been 3.by the end of last year 这个时间需要用过去完成时，出现by+时间是完成时的标记，加上last year是过去的时间，所以用过去完成时，把have-had 4.while引导的时间状语从句，表示持续性动作的从句要用进行时，所以是 walked-was walking 5.have去掉 6.have去掉 7.since-for

Answer 2

1bought 改为keep
2，gone 改为been
3 by 改为at
4 while 改为when
5 去掉have
6 去掉have
7 since 改为for

Answer 3

bought------keptgone------beenhave----hadwhile------asat----sincesince===for