By the time he retires, professor Baker _____ for almost forty years．
| A．will have taught | B．had taught |
| C．has taught | D．is teaching |
Pleaseask________nottoskateonthethinice.It’sverydangerous.
| A．they | B．them | C．their | D．theirs |
Wouldn’titbe______wonderfulworldifwecouldlivein______peace?
| A．a;the | B．the;不填 | C．a;不填 | D．the;the |
—Why did Sarah cry just now?
— She wanted a toy, _____ I can’t afford.
| A．it | B．one | C．that | D．what |
You’d better keep ______ when I take photos for you.
| A．silent | B．calm | C．still | D．mild |
I can’t afford _______ car.
| A．that expensive | B．a such expensive |
| C．a so expensive | D．that expensive a |