分析阿司匹林的结构,推知阿司匹林属于烃的衍生物中的 [ ]
A.羧酸类
B.醇类
C.醛类
D.酯类
AD
Water is (41) important of all the things we (42) and drink. Not many people understand this, (43) it’s quite true. The human body (人体) can go (44) food for a long time, but two (45) three days without water can usually (46) people die. Many people don’ t understand how much water the human body needs to work well and many people do not drink (47) , even (48) hot weather. Our body is (49) water, about 65% to 75%, ff we do not have enough water, we’ll (50) tired and many will get ill. So you see, how important water is to us all.
[A] in [B] for [C] on
蜈蚣全体共22个环节,第14~16环节为生殖环带。()