_______ is no doubt that the world is being smaller, due to the technological advances made by the computer.
| A．It | B．There | C．That | D．This |
Tom tried to __________ in German.
| A．understand himself | B．make himself understanding |
| C．make himself understood | D．make himself understand |
I wonder how many years ago ___________.
| A．did your father retire | B．has your father retired |
| C．your father retired | D．your father has retired |
He said that he would write to us but so far we ___________ from him.
| A．didn’t hear | B．haven’t heard | C．shouldn’t have heard | D．hadn’t heard |
__________ good exercise.
| A．Climbing hills is | B．Climbing the hill is |
| C．The climbing hills are | D．The climbing of hills are |
I don’t know who invented __________ telescope, but I think it is __________ most
useful invention.
| A．the, the | B．the, a | C．a, the | D．a, a |