四层螺旋CT的最薄扫描层厚是()
A.4mm×2.0mm
B.4mm×l.Omm
C.4mm×O.75mm
D.4mm×O.5mm
E.4mm×O.25mm
参考答案:D
--- What has your hobby brought you?
--- I think it has brought me happiness, especially it keeps me _____ .
A.upset
B.lonely
C.lazy
D.healthy
谷物中钙含量测定的原理是什么?