WHO推荐成人毛细血管采血法的采集部位（）
A.肘静脉
B.拇指
C.足跟
D.耳垂
E.左手环指指端内侧
参考答案：E
光在镜面上发生反射时，反射角________入射角（选填“等于”、“大于”、“小于”）；教室黑板发生“反光”现象，这是因为黑板太光滑，发生了 造成的（选填“镜面反射”、“漫反射”）。
When did you buy these new CDs?
I them for two days.
A. had B. have bought C. have had
