题干
— Paul is not very popular among his classmates.
一 Yeah. Because he often plays jokes on them.
A：makes fun of
B：fights with
C：studies with
答案(点此获取答案解析）
A
— Paul is not very popular among his classmates.
一 Yeah. Because he often plays jokes on them.
A：makes fun of
B：fights with
C：studies with
，且
与
垂直，
垂直，
与
的夹角的余弦值为（ ）