与小肠吸收营养物质有关的特征是 ( )
A:与大肠相连
B:与胃相连
C:有环形皱襞
D:有肠腺
— I stayed up late and ______ my lesson.
①洋葱根尖分生区细胞
②蚕豆的雄蕊
③大肠杆菌细胞
④蛙的红细胞
⑤蝗虫的精巢
下列化学方程式能正确表示所述内容的是( )
The first question is as as the second one. I can answer them easily.