题干
You have to be a fairly good speaker to ______listeners' interest for over an hour.
A：hold
B：make
C：improve
D：receive
答案(点此获取答案解析）
A
You have to be a fairly good speaker to ______listeners' interest for over an hour.
A：hold
B：make
C：improve
D：receive
在点(3,2)处的切线与直线 
垂直，则a等于 （ ）