系统干燥的目的是将水汽排出,防止催化剂受潮,设备填料生锈。
参考答案:对
Because they hadn’t booked a room in advance, there were______ left when they arrived at the hotel.
A.none
B.no one
C.nobody
D.nothing
胸内手术时下述何种方法更有效消除术中应激反应()
A.芬太尼+恩氟烷
B.丙泊酚+芬太尼
C.恩氟烷
D.异氟烷+芬太尼
E.硬膜外阻滞+氧化亚氮+恩氟烷