问题
选择题
—Is this your ruler?
—No, ______. [ ]
A. this is
B. it isn't
C. it is
D. this is not
答案
答案：B
搜题请搜索小程序“爱下问搜题”
—Is this your ruler?
—No, ______. [ ]
A. this is
B. it isn't
C. it is
D. this is not
答案：B
H+＋Cl─