About seventy percent of the population in China _______ farmers.
| A．is | B．be | C．are | D．will be |
．Mother ______ us stories when we were young .
| A．was used to tell | B．is used to telling | C．used to tell | D． used to telling |
·______down the radio ______ the baby's asleep in the next room．
| A．Turning | B． To turn | C．Turned | D． Turn |
．Charles Babbage is generally considered ______ is the first computer．
| A．to invent | B．inventing | C．to have invented | D．having invented |
．Little Jim should love ______ to the theatre this evening．
| A．to be taken | B．to take | C．being taken | D．taking |
．—The light in the office is still on．
—h，I forgot______.
| A．turning it off | B．turn it off | C．to turn it off | D．having turned it off |