1. The national park has a large collection of wildlife, _______ from butterflies to elephants.

     A. range               B.to range        C. ranging        D. ranged

2£®Jim has retired, but he still remembers the happy time _______ with his students.

     A. spent                                 B. to spend      

     C. having spent                          D. spending

3. To return to the problem of water pollution, I’d like you to look at a study_______ in Australia in 2012.

     A. conduct                               B. conducting    

     C. conducted                             D. having conducted