. ___ to nuclear radiation, even for a short time may produce variants（变异体）of genes in human bodies.
| A．Being exposed | B．Having exposed |
| C．Exposed | D．After being exposed |
Hardly returned home I realized I had left my key at the office.
| A．have I; when | B．had I; when | C．have I; than | D．had I; than |
Fortunately, the little girl the air – crash, but unluckily, the others on the flight were killed.
| A．was survived | B．has been survived | C．was surviving | D．survived |
--- How did the global financial crisis ?
--- I’m not quite sure. Anyhow, it is an very important problem facing us.
| A．come up | B．come about | C．come along | D．come around |
first time I met him in his office, he shook me by hand warmly and then introduce himself to me.
| A．The;不填 | B．The; The | C．The; a | D．A；不填 |
--- The apple tastes very nice. Could I have another apple, Sir?
--- .
| A．Yes, you could | B．Mind your hand | C．I’m sorry | D．Be my guest |