轴承正式组合安装时,在上部导轴承的上方和法兰处各装两块百分表,以监视轴线的移动。同一处两块百分表的夹角成( )。
A.45° B.90°C.135° D.180°
参考答案:B
根据句意,用括号内所给单词的正确形式填空。
1. This is Li Ming. He _____ (have) big hands.
2. I have two big _____ (foot).
3. —Does she _____ (have) a small mouth?
—Yes, she does.
4. Look! Her _____ (eye) are big.
5. My hair _____ (be) black (黑色的) and long.
何为太阳能热发电技术?