The study of natural history is not something to be left to biologists. In fact, their capacity _________ the time they can spend away from their offices is very limited.
__ ______ do you think of the book written by Dr. Wang? — In my opinion, it is not very interesting.
He stepped into the dark cave, _______ high above his head.
In our school, every student had free _______ to the library.
—Which do you prefer_______, English or Japanese? —English, I think.
The chemistry teacher demanded that the laboratory report _______ immediately after the experiment was done.