单选题：Did he find_____ hard to learn a foreign language? [ ]A. t..

Not having worked out the program, ______ leave the office. [ ]A. so he was forbidden toB. and he didn't want toC. his little son couldn't make him D. he couldn't free himself to

I' m sure that Laura' s latest play,_____, will prove a great success. [ ] A. if staging B. if it stages C. once staged D. once it stages

They want to make _______ clear to the public that they are doing an important and necessary job. [ ]A. thisB. thatC. itD. what

________sometimes keeps her awake at night ________ John is getting more and more quiet at home.[ ]A. That ; what B. What ; that C.It;thatD. Whether;what

When the earthquake happens, you'd better run to the area without high buildings; _____,you shouldkeep the height lower than table or bed and stay next to them.A. if any B. if notC. if necessary D. if some