地衣是一类独特的生物有机体,其体内合成了多种特殊的次生代谢产物,主要为缩酚酸、缩酚酸环醚 、 缩酚酮、二苯并呋喃等类化合物.A lot of secondary metabolites such and were produced by lichens, a class of unique organisms....
I don't try to memorize speeches word for word.我不会试图一字不落地记住讲话要说的内容。Official speeches in recent days have been larded with promises of democracy.近日官方在讲话中满口对民主的承诺。His forte is after - dinner speeches.他的特长是饭后演说.He has ...