I have a big family. In my family,there are 6 people—my father,my mother,my two sisters,my brother and me. My mother is Linda. My father is Mike. And our family name is Hand. My sisters are Gina and Sonia. They like baseball very much. My brother,David,is a lovely boy. He likes computer games. My name is Bob. I love my family.

小题1:How many多少people are there in the family?

A．Six

B．Seven

C．Five

D．Four小题2:What’s the writer’s作者的 full name全名？

A．Bob Hand

B．Bob Mike

C．David Hand

D．Linda Hand小题3:Linda has有      sons.

A．one

B．two

C．three

D．four小题4:My brother likes     .

A．baseball

B．computer game

C．pictures

D．basketball小题5:What does “love” mean意思是？

A．感谢

B．想起

C．喜欢

D．讨厌

如图所示，M是一块平面镜，位于透明液体之中，镜面水平向上放置，一细束光线a竖直向下射来，穿过液体射到平面镜上，现将平面镜绕水平轴在竖直面内顺时针转动15°角，光线经平面镜反射后在液面处分成两束，这两束光线恰好垂直，求；

（1）求该液体的折射率．

（2）若使光线经平面镜反射后在液面处恰好发生全反射，平面镜由初始水平位置绕水平轴在竖直面内顺时针转过的最小角度（用三角函数表示）．