皮肤出现焦痂的疾病是()
A.地方性斑疹伤寒
B.流行性斑疹伤寒
C.Q热
D.恙虫病
E.梅毒
参考答案:D
____ their service, the workers of the hotel are active in learning English. [ ]
A. Improving
B. To improve
C. Improve
D. Having improved
1gN2含a个分子,则阿伏加德罗常数可表示为( )
A.a/28mol-1
B.a mol-1
C.28a mol-1
D.a/14 mol-1