若一个部位显示的血流不清，下列哪项因素是错误的A.彩色频率过高

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问题单项选择题

若一个部位显示的血流不清，下列哪项因素是错误的

A.彩色频率过高

B.忘记打开彩色按键

C.彩色增益过小

D.超声束与血流方向垂直

E.该处无血流或血流小于显示阈值

答案

参考答案：B

选择题

Transit, a car made in Jiangxi Province, was sold nearly 50 000 units in 2012, with the total value ________ it was in 2008.

A．more than three times what

B．three more times than that

C．over three times than what

D．over three times of that

判断题

加入的助剂要与树脂的相容性好，助剂就分布均匀，所起的作用就可持久。但必须是对树脂分子机构起明显影响的物质。