问题
选择题
Seldom______computer games ever since he entered college.[ ]
A. did he play
B. has he played
C. he played
D. he has played
答案
答案：B
搜题请搜索小程序“爱下问搜题”
Seldom______computer games ever since he entered college.[ ]
A. did he play
B. has he played
C. he played
D. he has played
答案：B
分子中，含
个共用电子对
作氧化剂时，得到电子数一定是
的
溶液中硫离子数为
乙基（
）含有的电子数为