35.I don’t know how to change these ‘problems’ (　　　 )‘challenges’.

34.He is very strict (　　　 )his son (　　　 )his study.

33.Many students complains (　　　 )me (　　　 )their too much homework.

32.He solved the problem (　　　 )regarding problems (　　　 )challenges.

31.We can solve the problem (　　　 )learning to forget.

30.This room is used (　　 )our classroom (　　 )teaching English.

29.English is used (　　　 )the world (　　　 )computers.

28.Most people speak English (　　 )a second language.

27.It wasn’t easy (　　 )me to understand the teacher.

26.I don’t have a partner to practice English (　　　 ).