It was in the lab _____ was taken charge of by Professor Zhang ______ they did the experiment .
We have been trying hard to find out the ____________of the homeless man, but without luck, no one can tell who he is.
You can get to Hong Kong using different kinds of ________, by air, by sea or by land.
At the foot of the mountain _________ .
The young man was ________stealing possessions of his factory and put into prison.
Please keep us _________ of any change of address as soon as possible.