— Look! Black clouds are gathering.— Yes. A heavy rain is to come.A. possibleB. probableC

问题补充：

— Look! Black clouds are gathering.— Yes. A heavy rain is to come.

A. possible

B. probable

C. likely

D. really

答案：

A. possible

B. probable

(答案→)C. likely

D. really

解析：考查固定词组。固定词组be likely to do sth有可能做某事；句意：—看！乌云密布。—是的。一场暴雨马上就要来了。故C正确。