问题
选择题
13.______studying abroad can be hard, it can broaden your understanding of the word.
A．If
B．While
C．Because
D．Since
答案
答案：B
搜题请搜索小程序“爱下问搜题”
13.______studying abroad can be hard, it can broaden your understanding of the word.
A．If
B．While
C．Because
D．Since
答案：B
2AB(g)达到平衡的标志是