Question

A dark cloud is a ______ of thunderstorm.

1. A.
   symbol
2. B.
   sign
3. C.
   mark
4. D.
   signal

Answer 1

B
考查詞義辨析。Symbol 象征，sign 跡象，征兆，mark 標(biāo)記，signal 信號，句意：烏云就是閃電的征兆。根據(jù)句意選B。