(三级)国家秘密载体文件的秘密级别分为（）秘密三种。A、保密  B、绝密  C、机密

如图所示为电场中的某一条电场线，A、B、C是其上的三点。现用E_A、E_B、E_C表示这三点的电场强度，Φ_A、Φ_B、Φ_C表示这三点的电势，ε_A、ε_B、ε_C表示某一负的点电荷q在这三点具有的电势能，则必有

A．E_A＞E_B＞E_C

B．Φ_A＞Φ_B＞Φ_C

C．ε_A＞ε_B＞ε_C

D．ε_C＞ε_B＞ε_A

接触性出血

>CAPL处理的钢卷最大宽度为1600㎜。

乙状结肠扭转属于（）

A.低位肠梗阻

B.急性肠梗阻

C.完全性肠梗阻

D.动力性肠硬阻

E.闭袢性肠梗阻

Passage Three

How do songbirds learn their complex vocalizations a. They inherited by their parents. b. They have this naturally encoded in their genes. c. They learn by listening to others of their kind. d. They learn by listening to other kinds of birds.