14.Only by this means _______ complete the task ahead of time .
| A．you can | B．can you | C．should you | D．you should |
This is a______ but extremely difficult technology in the future.
| A．satisfactory | B．costly | C．promising | D．far-fetched |
They only hear while their hands and eyes are_________ occupied.
A other than B. no other than C. otherwise D. other ways
No sound and no voice______ for a while.
| A．have heard | B．has heard | C．has been heard | D．have been heard |
In America, ______ car is ______ popular means of transportation.
| A．the; a | B．a; the | C．the; the | D．the; / |
People think that ______ opening ceremony of the 29th Olympic Games is _____ great success.
| A．an; a | B．the ; a | C．the ;the | D．the ; / |