在三相系统中，（）是对称短路。 A.三相短路 B.两相短路 C.单相接地短路 D.两

“It looks as if he were drunk.” “So it does. _____.”

A．He’d better give up drinking

B．He shouldn’t have drunk so much

C．Health is more important than drink

D．I wonder why he is always doing so

According to IQ scores, you are smartest from 18 t0 25, but you're wiser and more                        experienced _______ increasing age.

A．for

B．with

C．at

D．of

正常尿中偶见什么管型（ ）。

A．白细胞管型

B．透明管型

C．红细胞管型

D．上皮细胞管型

蛇毒的主要有效成分是（）。

A．脂肪酶

B．胆固醇脂酶

C．磷脂酶A₂

D．磷脂酶C

E．磷脂酶D

柴油发动机燃油系统喷油嘴的作用是将燃油以何种形式喷人气缸（）。

A.水柱状

B.条状

C.雾状

D.水滴状