According to scientists, our mental abilities begin to _____ from the age of 27 after reaching the highest level at 22.
| A．differ | B．shrink | C．fail | D．decline |
Children will work actively if _______.
| A．praise | B．praised | C．praising | D．to praise |
Before I realized that what I said at the meeting did hurt him, he _________ without a word.
| A．drove away | B．was driving away | C．was driven away | D．had driven away |
—I wonder why Suzan looks worried today.
—I’m not sure, but she ________a small accident driving here.
| A．could have | B．might have | C．might have had | D．must have had |
He made it pretty clear from the beginning that we were going to war. _____ she still pretends that she knew nothing about it?
| A．Even though | B．How come | C．Now that | D．What if |
We’re living in a society_______exchanging presents is an important part in communication.
| A．which | B．when | C．why | D．where |