Responding to the public’s fascination with-and sometimes

undue alarm over-possible threats from asteroids, a scale

developed by astronomers rates the likelihood that a particular

asteroid or comet may collide with Earth.

A. a scale developed by astronomers rates the likelihood

that a particular asteroid or comet may

B. a scale that astronomers have developed rates how

likely it is for a particular asteroid or comet to

C. astronomers have developed a scale to rate how likely

a particular asteroid or comet will be to

D. astronomers have developed a scale for rating the

likelihood that a particular asteroid or comet will

E. astronomers have developed a scale that rates the

likelihood of a particular asteroid or comet that may.

答案是C，请讨论

will be to的用法看起来怪怪的。