问题
单项选择题 B型题
由于介质的密度不同而使光的传播方向发生改变的现象（）
A.荧光
B.折射
C.旋光度
D.酸度
E.密度
答案
参考答案：B
解析：偏振光旋转的角度为旋光度，左旋（逆时针方向）记为"-"，右旋（顺时针方向）记为"+"；由于介质的密度不同而使光的传播方向发生改变的现象称为折射现象；溶液中氢离子活度的负对数，可用来表示溶液酸度。
搜题请搜索小程序“爱下问搜题”
由于介质的密度不同而使光的传播方向发生改变的现象（）
A.荧光
B.折射
C.旋光度
D.酸度
E.密度
参考答案：B
解析：偏振光旋转的角度为旋光度，左旋（逆时针方向）记为"-"，右旋（顺时针方向）记为"+"；由于介质的密度不同而使光的传播方向发生改变的现象称为折射现象；溶液中氢离子活度的负对数，可用来表示溶液酸度。
| 阅读理解。 | |||||||||||||||||||||||||
| SUNNY SCHOOL We are a school for children of 6-15. We want a cook, a library assistant, a P. E. teacher and a language teacher.
| |||||||||||||||||||||||||
| 1. The children of _______ can go to Sunny School. | |||||||||||||||||||||||||
| A. 5 B. 16 C. 8 D. 3 | |||||||||||||||||||||||||
| 2. Tom is 20 years old, and he can speak Chinese and English. He also plays sports very well. So he can be _______ at Sunny School. | |||||||||||||||||||||||||
| A. a cook B. a P. E. teacher C. a language teacher D. a library assistant | |||||||||||||||||||||||||
| 3. _______ doesn't need to speak English. | |||||||||||||||||||||||||
| A. The language teacher B. The library assistant C. The cook D. The P. E. teacher | |||||||||||||||||||||||||
| 4.A library assistant must _______. | |||||||||||||||||||||||||
| A. be between 20 and 40 B. write English well C. be healthy and strong D. know different kinds of books well | |||||||||||||||||||||||||
| 5. This Wanted may (可能) come from _______. | |||||||||||||||||||||||||
| A. a newspaper B. a history magazine C. a story book D. a movie |