高速车螺纹时,硬质合金螺纹车刀的刀尖角应()螺纹的牙型角。
A.大于
B.等于
C.小于
D.大于或等于
参考答案:C
电子线照射乳腺胸壁野时不正确的是()
A.机架角为0°
B.装限光筒
C.患者仰卧位
D.升床
E.转小机头
---The 2010 World Expo (世博会) which will last 184 days will be held in Shanghai on May 1st.
--- ________ exciting news! We shall try our best to support it.
A.How
B.What
C.How an
D.What an