从生命活动的角度理解,人体的结构层次为( )
A:原子、分子、细胞器、细胞
B:细胞、组织、器官、系统
C:元素、无机物、有机物、细胞
D:个体、种群、群落、生态系统
看图读一读填空,把句子代码填在正确的横线上。
A. There's a blackboard in it. There are eighteen desks and eighteen chairs in it.
B. There are three books in it. C. There's a ruler. D. There's a big library.
A.因为 B.用 C.凭 D.用来
①公亦以此自矜。____
②以我酌油知之。____
③徐以杓酌油沥之。____
④以钱覆其口。____