.
Going on a trip to a far-away destination _________ be expensive and difficult, but it is very interesting.
| A．can | B．must | C．should | D．will |
A number of books in the library _______ been stolen so that the number of them ______smaller than before.
| A．have; is | B．has; is | C．has; are | D．have; are |
The growing speed of a plant is influenced by a number of factors, _____ are beyond our control.
| A．most of which | B．most of them |
| C．most of what | D．most of that |
It is usually warm in my hometown in March, but it _____ be rather cold sometimes.
| A．must | B．can | C．should | D．would |
I have reached a point in my life _____ I am supposed to make decisions of my own.
| A．which | B．where | C．how | D．why |
You will be successful in the interview ______ you have confidence.
| A．before | B．once | C．until | D．though |