用四爪卡盘夹持棒料,夹持部位较长时,可限制工件四个自由度。( )
参考答案:对
根据首字母或汉语提示完成单词。
1. The play will be ____________ (演出) at the City Theatre.
2. She is a ________ (成员) of a tennis club.
3. The p________ situation is peaceful, but in the past there was trouble in this area.
4. We have plenty of ________ (本地的) stores to choose from.
5. The girl's got her ears pierced, but she doesn't wear e________.
明确上消化道大出血原因的首选检查是()。
A.选择性腹腔动脉造影
B.纤维胃镜检查
C.隐血检查
D.B超
E.上消化道钡剂造影检查