其共轭酸因分子内氢键而稳定的是（） A．小檗碱 B．麻黄碱 C．伪麻黄碱 D．东莨菪

海关为履行职责，可以依法佩戴武器，海关工作人员在履行职责时可使用武器。( )

营养素

读漫画。某采购代理机构“敲竹杠”的行为，表明市场调节具有________的弱点。[ ]

A、自发性

B、盲目性

C、滞后性

D、灵活性

— I don't really like James. Why did you invite him? 

— Don't worry. He _____ come. He said he wasn't certain what his plans were. [ ]

A. must not

B. need not

C. would not

D. might not

有液体面包之称的酒是（）

A、米酒

B、果酒

C、葡萄酒

D、啤酒