It’s four o’clock in the afternoon. The boys in the pool.
A. is swiming
B. are swiming
C. are swimming
D. is swimming
网友回答
A. is swiming
B. are swiming
(答案→)C. are swimming
D. is swimming
解析：根据前文的内容. It’s four o’clock in the afternoon，可知答案为C，表示现在进行时。