题干
11．My father stayed in Japan only a few months, _____he went through a series of hardship.
A：during which time
B：in time of which
C：where
D：Whenever
答案(点此获取答案解析）
A
为坐标平面上三点，O为坐标原点，若
与
在
方向上的投影相同，则
与
满足的关系式为 （ ）