(保证答案正确)
1.Itis a teacher's job to make sure that sure that everyone (every one)of his students feels confident in preparing himself for the future.
多打了sure that 另外 everyone后不可接of所以要改为 every one(这道题有点怪下面题还可以2.There was such a long line at the exhibition so(so - that ) we had to wait for about half an hour.

By the time you get to New York,I (will )have already left for London.

Sometimes children have trouble to separate (to separate - in separating)fact from fiction and may believe that such things actually exist.

Reading among the lines,I would say that the officials are more worried that(that - what) they will admit.

The British constitution is by( by - to ) a large extent a product of the historical events described above.

There are signs which (which- that )restaurants are becoming more popular with families.

These books,which you can get at any bookshop ,will give you all the informations( informations - information) you need.

No matter how frequently performing( performing - performed ), the works of Beethoven always attract large audiences.

We didn't know his telephone number;otherwise we must have telephoned him.最后一题，我木有看出来，你写的是哪里。不过还是谢谢你。采纳你为满意回答。must- would对不起没看到