问题对对碰(把实验的具体操作、所观察到的实验现象和要研究的问题对应连接起来)
经常食用胡萝卜或适量动物肝脏,有助于预防( )
A. Because l can go swimming. B. These books are Tom's C. Yes, it is.
D. She is shopping E It's near the school.