问题
选择题
Listen! Can you hear someone _____ in the next room?[ ]
A. sing
B. to sing
C. is singing
D. singing
答案
答案：D
搜题请搜索小程序“爱下问搜题”
Listen! Can you hear someone _____ in the next room?[ ]
A. sing
B. to sing
C. is singing
D. singing
答案：D