M为数轴上表示2的点,将点M绕原点旋转180°到点N,则点N所表示的数为( )A

题型:选择题

问题:

M为数轴上表示
2
的点,将点M绕原点旋转180°到点N,则点N所表示的数为(  )
A.2B.-2C.
2
D.-
2
考点:实数的定义图形旋转
题型:选择题

临床上主要用于剧烈干咳的镇痛药为

A.吗啡

B.芬太尼

C.可待因

D.喷他佐辛

E.哌替啶

题型:选择题

离心泵停机后应立即()。

A、排空管道

B、关闭密封水,若冬天为防冻应微开密封水

C、通知电气人员断电

题型:选择题

断路器出厂验收,断路器机构箱外观完整、无损伤、接地良好,箱门与箱体之间的接地连接软铜线(多股)截面不小于()。

A.1mm2

B.2mm2

C.3mm2

D.4mm2

题型:选择题

汽车客运服务工作主要包括汽车客运站服务工作和()。

A.客运秩序管理工作

B.站内业务管理工作

C.车辆参营者服务工作

D.客运途中服务工作

题型:选择题

American higher education stands on the brink of chaos.
Never have so many spent so long learning so little. The present
crisis stems from the increasing widespread acceptance among62.______
faculty and administrators of the fatal educational principle
which a student should not be required to do any academic work 63.______
that displeases him. If a student prefers not to study science or history
or literature, he has allowed to attain his degree without studying any 64.______
science, history, or literature.
In America the attempt is being made to provide students
with what is advised as a liberal education without requiring by them 65.______
the necessary self-discipline and hard work. Students have been led to
believe they can achieve without effort, that all they need to do is skip
light-heartedly down the merry road to learning. Fortunately, that road 66.______
is no more than a detour (弯路) to the dead end of ignorance.
we must realize that becoming an educated person is a
difficult, demanded enterprise. Just as anyone who regards intense 67.______
physical training as a source of delight would be thought a fool, for
we all know how much pain such training involves, but anyone who68.______
speaks intense mental exertion as a source of joy ought to be thought 69.______
equally foolish, for such effort also involves pain. It is painful to have
one’s ignorance exposing and frustrating to be baffled by intellectual 70.______
subtleties. Of course, there can be joy in learning as there can be in sport.
But in both cases a joy is the result of overcoming challenges and can’t71.______
be experienced without toil.

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