I think the music is great, it is worth ______.
| A．to listen | B．to listen to | C．listening | D．listening to |
The World Health Organization has given some advice on________to protect us from being infected(感染)with H7N9．
| A．how |
| B．what |
| C．where |
| D．when |
—What do you usually help your mother________？
—I often do the dishes．
| A．to doing |
| B．to do |
| C．doing |
| D．does |
It took him one hour________his homework．
| A．do | B．to do | C．doing | D．to doing |
The weather is too dry．Those trees need________．
| A．watering | B．to watering |
| C．to water | D．watered |
They had trouble________complete sentences．
| A．to make up | B．make up |
| C．to making up | D．making up |