题干
The students should _________ when the teachers give the lessons.
A：take notes
B：take out
C：take turns
答案(点此获取答案解析）
A
The students should _________ when the teachers give the lessons.
A：take notes
B：take out
C：take turns
=α
+β
，其中α，β
R，α+β=1，则点C的轨迹为