恙虫病治疗首选()
A.氯霉素
B.磺胺
C.青霉素
D.庆大霉素
E.红霉素
参考答案:A
Giving up my job to go back to fulltime education was a big ________,but now I know it was the best decision I ever made. (2011·湖北,22)
A.project
B.commitment
C.competition
D.ambition
在比例尺是1:4000000的地图上,图上距离1厘米表示实际距离______千米.也就是图上距离是实际距离的______,实际距离是图上距离的______倍.