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【单选题】
用布氏漏斗和吸滤瓶连接真空泵过滤沉淀后,正确的操作是( )。
A.
先关真空泵,拔下抽滤瓶上的橡皮管,再取下漏斗
B.
先把沉淀和滤纸一起取出再关上真空泵
C.
先取下漏斗,再关上真空泵
D.
先拔下抽滤瓶上橡皮管,关上真空泵
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【单选题】电气元件中储能元件有( )
A.
电阻;
B.
IGBT;
C.
电容;
D.
二极管。
【单选题】— Julia won the prize this time again. — She worked hard when she was at school, which ___her success in her career. [     ]
A.
depended on
B.
contributed to
C.
brought about
D.
cared for
【简答题】继电器的继圈两端并联二极管、压敏电阻、电容阻电路的作用是什么?
【多选题】希罗多德和修昔底德是古希腊著名的史学家,他们的史学著作是( )。
A.
《历史》
B.
《理想国》
C.
《伯罗奔尼撒战争史》
D.
《被缚的普罗米修斯》
【单选题】光照光敏二极管,引起光敏二极管发生显著变化的量是()。
A.
电容
B.
电感
C.
电阻
D.
温度
【单选题】"Julia", written by Lennon, was named for and _____ to his mother.
A.
distributed
B.
attributed
C.
dedicated
D.
contributed
【单选题】--- Julia, what were you doing when Anna called you? --- I ________ my housework and was starting to take a bath.
A.
had finished
B.
have finished
C.
were finishing
D.
will finish
【简答题】自关断器件保护电路中电容、电阻及二极管的作用描述错误的是 A利用电容两端电压不能突变的原理延缓关断时集射电压上升速度 B电阻作用是限制器件导通时电容的放电电流 C二极管的作用是在关断过电阻旁路,以充分利用电容的稳压作用 D电阻的作用是分压,以降低管压降
【单选题】Which of the following underlined words will be stressed when Julia responds to the person who has mistaken her for Julian?
A.
My name is Julia, not Julian.  A
B.
My name i s Julia , not Julian.  B
C.
My name i s Julia, not Julian. C
D.
My name i s Julia, not Julian.  D
【单选题】能量通过约1.5亿km的空间到达地球的大气层附近时,其辐射能量密度约为(),这个值叫太阳常数。
A.
1.8kw/m²
B.
1kw/m²
C.
2kw/m²
D.
1.4kw/m²
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