构成细胞膜、细胞质和细核的主要化合物是有机物，水和无机盐在活细胞中并不重要．　

    Hi, I'm Mary. I'm a pupil. I usually get up at six on weekdays. I have tea and bread for breakfast. I have two friends. One is Lucy and the other is Lily. Lucy often gets up at six thirty. She likes bread and milk. But Lily likes hamburgers and tea. She doesn't like milk at all.

写出下列等式中未知的分子或分母．

－Mum, can I eat ________ cakes?

－Sorry. There aren't ________ at home