______ like to play tennis.[ ]
A. Both we
B. We both
C. Both of we
D. All of we
答案:B
塑料根据其受热时性质不同,可分为______塑料和______塑料,二者在性质上不同之处是:______.
牙周手术后常局部应用以控制菌斑的是()
A.麝香草酚
B.氯己定
C.四环素
D.磺胺类
E.甲硝唑