与光导纤维制造的光纤相比，由多成分玻璃纤维制成的光导纤维（ ）。
A．成本低
B．传输损耗小
C．性价比好
D．传输距离较远
参考答案：C
—Do you think it will rain tomorrow?
— . It hasn't rained for a whole month! It's too dry. [ ]
A. I hope so
B. I hope not
C. I'm sure it will
She is always busy ______ the palace (豪宅). [ ]
A. showing foreign friends around
B. to show foreign friends around
C. showing foreign friends to visit
D. to show foreign friends to visit
