Much labor would have been saved if the electronic computers_____________ before.
| A．had invented | B．were invented |
| C．should have been invented | D．had been invented |
It is pleasant to play ______ game of ______ table tennis ______ summer afternoon.
| A．a...the...on the | B．a...X...on a | C．the...the...in the | D．the...X...in a |
When we saw his face, we knew _____ was bad.
| A．the news | B．some news | C．a news | D．news |
Biology is _____.
| A．science of life | B．science of the life | C．the science of the life | D．the science of life |
_____ of them knew about the plan because it was secret.
| A．Some | B．Any | C．No one | D．None |
"How many elephants did you see?" "_____".
| A．None | B．No one | C．Not many ones | D．No many |