When _______a hand, one should say “Thank you” or “It’s very kind of you.”
For _______information about present national boundaries, we’d better refer to an up-to-date map.
When you are in trouble, you may _______ your teacher and classmates for help.
The number of the people who can afford to buy their own house ______ more than 60%,but a number of houses _______.
I didn’t get a pay rise, but that wasn’t the right reason _______I left.
He started to study ecology and decided to _______his whole life to the science.