均方值Ψx2与均值μx、方差σx2的关系是Ψx2=μx2-σx2。 ( )
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Lily likes ________ and ________ , so she chooses Guilin
A. mountain
B. hill
C. river
D. old town
Xiao Ming is interested in __________ and ___________, so he wants to visit the Bird's Nest.
A. grassland
B. architecture
C. sports
D. city
David is interested in _____ , _____ and _____, so he chooses to visit the museum.
A. beach
B. history
C. art
D. culture
CT增强扫描使用的对比剂为
A. 硫酸钡
B. 有机碘
C. 泛影葡胺
D. Gd-DTPA
E. 二氧化碳
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