代数式-3x22，x2+1π，78，x+1x，5b3a的分式有（ ） A．1个 B．

患者目赤翳障，烂弦风眼。首选

A．明矾

B．雄黄

C．硼砂

D．蜂房

E．炉甘石

在负荷较小或地区供电条件困难时，二级负荷的供电系统可由一回6kV及以-亡的专用电缆线路供电，而且应采用两根电缆组成的线路供电，其每根电缆应能承受()的二级负荷。

A．50%

B．80%

C．90%

D．100%

Why have the Americans developed space shuttle according to the passage

Which of the following statements is NOT true according to the passage

A．The term "averted vision" refers to the act of looking out of the comers of one’s eyes.
B．If you want to see very faint things, you should better look sideways rather than straight on.
C．The receptors located in the eye’s center are less sensitive to dim light.
D．To "look" is to see something straight ahead.

从业人员在入岗前必须掌握的知识？

在用单价法编制施工图预算过程中，单价是指（）。

A．预算定额单价 

B．材料单价 

C．人工单价 

D．实际定额单价