皮带输送机的主要作用就是靠它的皮带将工件输送到下一工序,通过()或速比控调节到所需速度进行工作的。
参考答案:变频器
阅读理解并判断正(√)误(×)。
I have a good friend. His name is Tom. He is in a school in England. He goes to school from Monday to
Friday. He likes basketball very much. He can speak a little Chinese. But he can't write in Chinese. He often
writes to me in English. He knows a lot about China. He wants to come to China very much.
( ) 1. Tom is a good friend of mine.
( ) 2. Tom studies in England.
( ) 3. Tom speaks Chinese very well.
( ) 4. Tom doesn't like basketball.
( ) 5. Tom studies at school five days a week.
结膜炎最基本的体征是
A.结膜水肿
B.结膜出血
C.结膜充
D.分泌物增多