为预防感染,诊断性刮宫术后应禁盆及性生活()
A.1周
B.2周
C.3周
D.4周
E.6周
参考答案:B
As nobody here knows what is wrong with the machine, we must send for an engineer to______the
problem. [ ]
A. handle
B. raise
C. face
D. present
滑石的主要成分是()
A.硫酸钙
B.含水硫酸钠
C.四硼酸钠
D.碳酸钙
E.含水硅酸镁