下列物质属于纯净物的是[ ]
A．雪碧饮料
B．食醋
C．加碘食盐
D．蒸馏水
答案：D
气闸门
China has demanded the US to reduce and ____ stop its military air and sea spying to avoid naval confrontation (海上对抗). [ ]
A. extremely
B. slightly
C. gradually
D. eventually
