题干
—Why didn't your sister talk with me?
—She is a _______ girl. She is afraid of speaking before strangers (陌生人).
A：good
B：happy
C：shy
D：clever
答案(点此获取答案解析）
C
的图象与
轴，
轴分别相交于A，B两点，点C在AB上以每秒1个单位的速度从点B向点A运动，同时点D在线段AO上以同样的速度从点A向点O运动，运动时间用
（单位：秒）表示．