( )1. Sometimes he feels like ______ to give up.
A, to want B, wanting C, want D, wanted
( )2. There _____ a lot of trees here, but now it has become desert.
A, is B, awe C, used to be D, used to being
( )3 You should _______, if you have some new ideas.
A, try them on B, try them out C, try on them D, try out them
( )4. Many rivers ______.
A, have became polluted B, have become polluted
C, have been polluting D, have become polluting
