2. Sit down and ___________ some water, please.
A. to drink                      B. drinking                C. drink                     D. drinks
3. It’s useful (有用的) ___________ to English songs. 
A. to listen                      B. listening                C. listen                    D. listens
4. Let’s___________ the door. 
A. closing                  B. close                     C. to close                       D. go to close