秋水仙碱( )
A.异喹啉(吗啡烷)类生物碱B.吲哚类生物碱C.有机胺类生物碱D.二萜生物碱E.异喹啉类生物碱
说明下列生物碱的结构类型
参考答案:C
----- Do you have clothes ______? I’ll wash them for you. ------No, thank you. I will wash them myself.
A.to be washed
B.to wash
C.washing
D.being washed
用两根轻质的绳子AB和BC吊一个0.5kg的灯。如果BC绳处于水平,AB绳与水平夹角为60°,求绳AB和BC的张力拉力。(g=10N/kg)(10分)