If they _______ what I was saying, they'd know what I was talking about.
| A．took the trouble to listen to | B．had trouble listening to |
| C．take the trouble to listen to | D．have trouble listening to |
to sunlight for too much time will do harm to one’s skin.
| A．Being exposed | B．Exposed |
| C．Having exposed | D．After being exposed |
They appearedme, so I had to explain to them.
| A．misunderstanding | B．misunderstood |
| C．to be misunderstood | D．to have misunderstood |
If China’s space technology has achievedbreakthrough in this field, it really is
amazing wonder.
| A．the; an | B．a; an | C．不填; the | D．a; 不填 |
Though he is in his late sixties, the well-known biolo
gist begins each day ____ a sense of adventure and a sense of curiosity.
| A．in | B．with | C．of | D．at |
The chairman was about to declare the conference open ____ the lights went all out.
| A．as | B．while | C．then | D．when |