题干
Our school doesn't students' staying in the classroom too long. We think they should have time for sports.
A：advocate
B：admit
C：assess
D：approach
答案(点此获取答案解析）
A
、
分别是射线
上的两点，给出下列向量：
；②
；③
；
；⑤
.
为起点，终点在阴影区域内的是( )