题干
—Is your brother running in the park?
—No, he _________ in the river.
A：swim
B：swims
C：swimming
D：is swimming
答案(点此获取答案解析）
D
—Is your brother running in the park?
—No, he _________ in the river.
A：swim
B：swims
C：swimming
D：is swimming
m/s2），则
