A:x1<x3<x2
B:x2<x1<x3
C:x1<x2<x3
D:x3<x1<x2
乙烯在不同的条件下可被氧化生成不同产物.如图所示:
已知:取0.62g A与过量的金属钠完全作用后,生成224mL(标准状况)气体.B的沸点低(10.7℃),B不能发生银镜反应而C能.D有酸性、强氧化性,可用于消毒杀菌.
完成下列填空:
消化食物和吸收营养的主要场所是____,它也是消化道中最____ 的部分.
John: What do you do on Sundays?
Tom: I read books and watch TV. What do you do on Sundays?
John: I do my homework . What about you, Mary?
Mary: I clean my room and watch TV.
John: You're helpful.
As I joined the big crowd, I got________from my friends.