The dresses in this company are available in a great _____ of sizes and styles.
| A．combination | B．variety | C．couple | D．amount |
The world’s population has grown by ______ it was in 1800.
| A．more than six times that | B．six times more than that |
| C．more than six times what | D．six times as many as |
He failed in the driving test again. He_______.
| A．must have disappointed | B．must have been disappointed |
| C．might be disappointed | D．couldn’t be disappointed |
In his first speech as victor, Obama said, “There are many who won’t agree with every decision or policy I make as ________ president, and we know that government can’t solve every problem. But I will always be honest with you about ________ challenges we face.”
| A．a; / | B．the; the | C．/; the | D．the; / |
To keep healthy, most retired people _______ jogging as a regular form of exercise.
| A．take up | B．take on | C．give up | D．hold out |
The young man stopped and looked back as if ______ whether he was being followed.
| A．seeing | B．to have seen | C．having seen | D．to see |