Joan is an American girl. She lives in China now. She is in my class. Her parents work in China, too, but her brother works in the U.S.A. He often writes letters to them. Joan likes Chinese class very much, and likes speaking Chinese with us after class. Her father teaches us English well. We all like his class. On Sundays, Joan goes to the People's Park with her father and mother. Sometimes she goes shopping with her mother. They like the Chinese food very much. It's a happy family.

从长方体木块中，挖掉一小块后(如下图) ，它的表面积(       ) 。

下列关于蛋白质的说法中不正确的是（    ）

下面的句子，哪种译法最符合课文原意？请将相应的字母、填入括号内。

战于长勺。（    ）

计算．