丁卡因的特点是()。
A.不用于表面麻醉
B.局麻作用弱
C.作用持续时间短
D.穿透力差
E.毒性大
参考答案:E
解析:丁卡因的毒性大,是普鲁卡因的10~12倍。
—Could you tell me_____________?
—Certainly. In half an hour.
A. when the high speed train will arrive
B. when the high speed train arrived
C. if the high speed train has arrived
什么是突出煤层?什么是突出矿井?