21．The doctor couldn’t answer the question _____ the patient could survive that night．
| A．if | B．that | C．whether | D．What |
I used to drink a lot of tea but these days I ＿＿coffee.
| A．prefer | B．preferred | C．have preferred | D．am preferring |
Look at this! I＿＿some magazines and＿＿this letter.
| A．was looking through； found | B．am looking through； find |
| C．looked through； had found | D．had looked through； finding |
The train ＿＿＿＿＿ at the present speed until it reaches the foot of the mountain at about nine o’clock tonight.
| A．went | B．is going | C．goes | D．will be going |
— Did he notice you enter the room?
— I don’t think so. He＿＿to the radio with his eyes shut.
| A．listened | B．was listening | C．has listened | D．had listened |
— Tom, did Mr. Li join you in your discussion?
— No, he＿＿, but he happened to have fallen ill.
| A．would like to | B．will | C．was to have | D．was going to join |