_____in the sports world，a sportsman needs to train constantly to keep himself in best condition．
| A．Survive | B．Surviving |
| C．To survive | D．Survived |
I was ___ in the middle of my call because I had no more pennies to put in the box.
| A．broken in | B．cut off |
| C．hung up | D．put down |
Once ___ what to do, these computers will show great power in carrying it out.
| A．to teach | B．teaches | C．teaching | D．taught |
He talked about the classmates and the school ___ he had visited.
| A．which | B．that | C．who | D．about which |
Americans eat __ vegetables per person today as they did in 1910.
| A．more than twice | B．as twice as many |
| C．twice as many as | D．more than twice as many |
I wonder if you know it ___ .
| A．in all | B．all in all | C．above all | D．at all |