题干
It was his wife___ left him without saying goodbye.
A：who
B：which
C：whe
D：in which
答案(点此获取答案解析）
A
A：who
B：which
C：whe
D：in which
从地面以初速度v0竖直上抛的同时，将另一相同质量的小球
从距地面
处由静止释放，两球恰在
处相遇（不计空气阻力）。则