1) 1.I have written a letter.
2.We have never been to London.
3.My town is cleaner than New York.
4.We travel a lot in summer.
5.A lot of animals live in our forests.
4)1.used to/didn't use to
2.didn't use to
3.didn't use to
4.didn't use to
5.used to/didn't use to
6.didn't use to
7.used to/didn't use to
