石膏是缓凝剂,石膏的掺量越多,水泥的凝结时间越长。
参考答案:错
It's said that more than 100 _______ will attend this meeting in Shanghai. [ ]
A. man teachers
B. woman teachers
C. men teachers
D. womans teachers
慢性宫颈炎病理分为()、()、()、()、()。