问题
选择题
It is necessary _____ others when they are in trouble.[ ]
A. of us to help
B. of us helping
C. for us to help
D. for us helping
答案
答案：C
搜题请搜索小程序“爱下问搜题”
It is necessary _____ others when they are in trouble.[ ]
A. of us to help
B. of us helping
C. for us to help
D. for us helping
答案：C