Although the causes of cancer _____, we do not yet have any practical way to prevent it.
| A．are being uncovered |
| B．have been uncovering |
| C．are uncovering |
| D．have uncovered |
It is reported that two schools, _________are being built in my hometown, will open next year.
| A．they both | B．which both | C．both of them | D．both of which |
He tried his best to solve the problem, _______difficult it was.
| A．however | B．no matter | C．whatever | D．although |
—Which driver was to blame?
—Why, _______！It was the child’s fault, clear and simple. He suddenly came out.between two parked cars.
| A．both | B．each | C．either | D．neither |
—What do you want to do
next? We have half an hour until the basketball game.
—_______________. Whatever you want to do is fine with me.
| A．It just depends | B．It’s up to you | C．All right | D．Glad to hear that |
I_______________ that all windows are shut. I did it.
| A．make sure | B．am sure | C．make clear | D．am clear |