细胞膜的成分中含量较高的物质是( )
看图，读一读，选择正确的句子。
A. Hello. This is my mother. I loveher.
B. Hello. I'm Grandma and this is yourGrandpa.
C. Look, this is my classmate. His nameis Bob.
D. Good morning, Kitty.
20×52－15×52____20×52－52
