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【单选题】
两个同周期简谐振动曲线如图所示,则 的相位比A.
落后
B.
超前
C.
落后π
D.
超前π
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皮皮学刷刷变学霸
举一反三
【单选题】下列各组物质中既有离子键又有共价键的是
A.
KOH、H 2 SO 4 、NH 4 Cl
B.
CaO、Na 2 CO 3 、NH 4 HCO 3
C.
K 2 O 2 、NaOH、K 2 SO 4
D.
HclO、Al 2 O 3 、MgCl 2
【单选题】下列各组物质中，每种物质都是既有离子键又有共价键的一组是( )
A.
NaOH H 2 SO 4 (NH 4 ) 2 SO 4
B.
MgO Na 2 SO 4 HNO 3
C.
Na 2 O 2 KOH Na 3 PO 4
D.
HCl Na 2 O MgCl 2
【单选题】Which of the following is NOT true?
A.
Seventy million people have an eating disorder in the world．
B.
More than 1／2 0f the women and 2／3 0f the men in Britain have weight problem．
C.
More than 1／4 0f adults and 1／5 0f children in USA weigh too much．
D.
Clothing factories and magazines showed images of women of all shape．
【单选题】听力原文：M: You must have been driving at seventy miles an hour. Didn' t you see the speed limit? W: I can' t have been driving that fast. M: I was doing eighty when I overtook you. What were they talking...
A.
The driving speed of the woman.
B.
How fast they should drive.
C.
The speed limit.
D.
The driving speed of the man.
【单选题】配合回归直线方程对资料的要求是( )
A.
因变量是给定的数值,自变量是随机的
B.
自变量和因变量都是随机的
C.
自变量是给定的数值,因变量是随机的
D.
自变量和因变量都不是随机的
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