具有葡萄糖反应现象的非吸入性麻醉药是（）
A.戊巴比妥钠
B.静松灵
C.水合氯醛
D.氟烷
E.硫喷妥钠
参考答案：A
____ their service, the workers of the hotel are active in learning English. [ ]
A. Improving
B. To improve
C. Improve
D. Having improved
