The invention of_________ paper was a great contribution to________human civilization.
| A．a;a | B．the;the | C．/;/ | D．the;/ |
________ the present unemployment continue, the society would face a more
troublesome situation.
| A．Would | B．Should |
| C．Might | D．Could |
I ________ the pages together with a paperclip.
| A．attached | B．fixed |
| C．fastened | D．tied |
The dictionary is being printed and it will soon ________.
| A．turn out | B．come out |
| C．start out | D．go out |
—The plane is due to take off at 7：50 from the airport.
—________ we fail to arrive there on time?
—Try to take another flight then.
| A．What if | B．As if |
| C．Even if | D．Only if |
The traditional view is ________ we sleep because our brain is “programmed” to make us do so.
| A．when | B．why | C．whether | D．that |