15．– How cold it is! I wonder how grass survive under such heavy snow．
--Don’t worry．There is a lot of air in loose snow which _______．
| A．keeps out the cold | B．keeps the cold away |
| C．keep off the cold | D．keep the cold up |
The thieves _____ him _____ in the park, took his wallet and escaped.
| A．held .. back | B．held .. up |
| C．held .. on | D．held .. out |
My house is very _____ for getting to work as it is only a few minutes from the station.
| A．comfortable | B．suitable | C．convenient | D．available |
Be careful how you _____ that jug, it will break very easily.
| A．pour | B．operate | C．handle | D．employ |
—Will you stay for lunch?
—Sorry, ________. My brother is coming to see me.
| A．I mustn’t | B．I can’t |
| C．I needn’t | D．I won’t |
How ________ you say that you really understand the whole story if you have covered only a part of the article?
| A．can | B．must |
| C．need | D．may |