汽油的安定性能是指在储存、运输或使用过程中,()
A、汽油抵抗被氧化的能力
B、汽油生成胶质的倾向性
C、汽油变质的可能性
D、汽油的挥发性
参考答案:A, B, C
唾液功能有()
A.机械清洁
B.润滑和保护
C.缓冲作用
D.抗微生物
E.以上都是
小题1:When I was young, my teacher told me that the early bird _________ the worm.
小题2:I ________the Great Wall as soon as I arrive in Beijing.
小题3:---Why didn’t you answer my phone?
---- Sorry. I _________ on a patient the whole afternoon.
小题4:I __________ this magazine. Will you please show me another?
小题5:_________ the letter ______ to the manager of the company yesterday?