20．Helen devoted herself__________to her research and became a top scientist in the field of applied physics.
| A．seriously | B．extremely | C．entirely | D．Strictly |
It was thought to be ______ adventure for him to walk across ______ Sahara Desert alone.
| A．an; the | B．the, / |
| C．/; the | D．an; a |
The teacher was worried about the boys in her class, for they spent ______ time playing computer games.
| A．large amount of | B．a large number of |
| C．a large amount of | D．large numbers of |
Luckily, there is a hospital ____ and they soon took the wounded man there.
| A．nearly | B．beyond | C．nearby | D．away |
My son ____ the examination, but he wasn't careful enough.
| A．might be able to pass | B．must have passed |
| C．could have passed | D．were able to pass |
---- Must we clean the house now?
-----No, you _______.
| A．needn't | B．may not |
| C．mustn't | D．can't |