指向性是指声束集中向两个垂直方向辐射的性质。

题型:判断题

问题:

指向性是指声束集中向两个垂直方向辐射的性质。

考点:无损探伤工无损探伤工(中级)无损探伤工(中级)题库
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系统性红斑狼疮患者最常见(发生率>20%)的消化系统症状包括()

A.恶心、呕吐

B.食欲减退

C.胃肠道血管炎

D.肝硬化

E.进食哽噎

题型:判断题

.  Your mouth will be opened and your teeth will be shown when you laugh. However, the h____(1)_____ those teeth are, the happier you look. Strong, healthy teeth can help you eat the right food to help you g_____(2)______. They also help you speak clearly. But do you know how to take care of your teeth? These should be f_______(3)______.

Brush your teeth twice a day after breakfast and before bedtime. If you can, brush after lunch or after eating sweet cakes. T____(4)_____ your time while brushing. Spend at least 3 minutes each time you brush. Brush all of your teeth, not just the f____(5)_____ ones. Spend some time on the teeth along the s_____(6)______ and in the back.  

Be sure the t____(7)_____ you use is soft and should be changed every three months or even less.

Learn how to floss(用牙线清理) your teeth, which is a very important way to keep them healthy. It feels s when you do it at first, but soon you’ll get used to doing it. The floss cleans up food that’s h____(8)_____ between your teeth.

Brushing and flossing keep your teeth healthy. You also need to c______(9)______ about what you eat and drink. Eat lots of fruits and vegetables and drink water i____(10)____ of drinks.

题型:判断题

下列哪些内容是测量误差的分类内容( )。

A.系统误差

B.疏忽误差

C.偶然误差

D.相对误差

E.绝对误差

题型:判断题

对放射治疗不敏感的恶性肿瘤是哪种()

A.尤文肉瘤

B.恶性淋巴瘤

C.未分化癌

D.浆细胞肉瘤

E.恶性黑色素瘤

题型:判断题

商家对商品的有效描述没有符合商品实际或者言过其实的行为,是指违反()。

A、淘宝商城商家店铺规范

B、侵犯其他商家权益

C、淘宝商城商品如实描述服务规则

D、淘宝商城正品保障服务规则

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