问题
选择题
---Listen! Who ______ in the next room?
---I think Sam is.
A．sing
B．sings
C．singing
D．is singing
答案
答案：D
根据listen 可判断时态为现在进行时，故选D
搜题请搜索小程序“爱下问搜题”
---Listen! Who ______ in the next room?
---I think Sam is.
A．sing
B．sings
C．singing
D．is singing
答案：D
根据listen 可判断时态为现在进行时，故选D