问题
单项选择题
This maths problem is easy（）
A.work out
B.to be working out
C.worked
D.to work out
答案
参考答案：D
搜题请搜索小程序“爱下问搜题”
This maths problem is easy（）
A.work out
B.to be working out
C.worked
D.to work out
参考答案：D