He found very difficult the math problem．
| A．that；to solve | B．this；solving |
| C．it；to solve | D．it；solving |
I never doubt ________ his advice is of great _________ to me.
| A．that; helpful | B．if; help |
| C．whether; helpful | D．that; help |
—Is David coming by train?
—He should, but henot. He likes driving his car.
| A．can | B．need | C．must | D．may |
US First Lady Michelle Obama encouraged students to study abroad in herwhen visiting Peking University on March 22, 2014.
| A．story | B．speech | C．letter | D．diary |
Be quick, ___________ we’ll be late for the meeting.
| A．and | B．but | C．so | D．or |
________ useful advice you gave us!
| A．How a | B．What an | C．What | D．How |