Air and the sun's rays create much distortion, and whatever tends to _____ their influence is useful to the astronomer.

　　A. exclude  B. eliminate  C. extinguish  D. impose

Air and the sun's rays create much distortion, and whatever tends to _____ their influence is useful to the astronomer.

A. exclude  B. eliminate  C. extinguish  D. impose

Air and the sun's rays create much distortion, and whatever tends to _____ their influence is useful to the astronomer.

1. A.
   exclude
2. B.
   eliminate
3. C.
   extinguish
4. D.
   impose

Air and the sun's rays create much distortion, and whatever tends to _____ their influence is useful to the astronomer.

　　A. exclude  B. eliminate  C. extinguish  D. impose