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【单选题】
数字电路中晶体管大多工作于 ( ) 。
A.
放大状态
B.
短路状态
C.
击穿状态
D.
开关状态
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【判断题】干亲又称拟制血亲、准血亲,指的是本无血缘关系,主要是基于收养关系或结拜关系而产生的。但干亲不是亲属关系的组成部分。()
A.
正确
B.
错误
【单选题】AMERICA'S central bank sent a clear message this week. For the second consecutive meeting, the Federal Open Market Committee, the central bank's policy-making committee, left short term interest rates...
A.
interpret the message from the central bank,
B.
justify the rise of short term interest rates.
C.
illustrate what is weakness and undue growth.
D.
contrast different views on economic indices.
【单选题】设y1、y2是二阶常系数线性齐次方程y'+p1y'+p2y=0的两个特解,C1、C2为两个任意常数,则下列命题中正确的是
A.
C1y1+C2y2为该方程的通解
B.
C1y1+C2y2不可能是该方程的通解
C.
C1y1+C2y2为该方程的解
D.
C1y1+C2y2不是该方程的解
【单选题】设f 1 (x)和f 2 (x)为二阶常系数线性齐次微分方程y″+py′+g=0的两个特解,若由f 1 (x)和f 2 (x)能构成该方程的通解,下列哪个方程是其充分条件()?
A.
f 1 (x)·f′ 2 (x)-f 2 (x)f′ 1 (x)=0
B.
f 1 (x)·f′ 2 (x)-f 2 (x)·f′ 1 (x)≠0
C.
f 1 (x)f′ 2 (x)+f 2 (x)·f′ 1 (x)=0
D.
f 1 (x)f′ 2 (x)+f 2 (x)f′ 1 (x)≠0
【单选题】“干血”是指( )
A.
瘀血日久
B.
血滞
C.
血郁化热
D.
瘀血新成
E.
血热互结
【多选题】多媒体的发展包括以下哪几个阶段?
A.
初露端倪
B.
趋于成熟
C.
全面发展
D.
继续发展
【单选题】The word 'message' in the last paragraph means
A.
printed news.
B.
contact.
C.
meaning.
D.
central idea.
【单选题】设f1(χ)和f1(χ)为二阶常系数线性齐次微分方程y〞+py′=0的两个特解若由f1(χ)和f1(χ)能构成该方程的通解,下列哪个方程是其充分条件?
A.
f1(χ)·f′2(χ)- f2(χ) f′1(χ)=0
B.
f1(χ)·f′2(χ)- f2(χ) f′1(χ)≠0
C.
f1(χ)f′2(χ)+ f2(χ) ·f′1(χ)=0
D.
f1(χ)f′2(χ)+f2(χ) f′1(χ)≠0
【单选题】设对称振子总长度为 2 l ,下列关于有效长度的计算正确的是【】。
A.
短振子的有效长度总是 l
B.
半波振子的有效长度是 2 l /π
C.
全波振子的有效长度是 2 l /π
D.
波腹电流和输入电流是不相等的
【单选题】America's central bank sent a clear message this week. For the second consecutive meeting, the Federal Open Market Committee, the central bank's policy-making committee, left short-term interest rates...
A.
strongly believed in economic recovery.
B.
took for granted economic expansion.
C.
were cautious in their excessive investment.
D.
had doubts about the effects of price pressure.
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