题目

— Mum, can you give me some advice on how to behave myself at the table?            — Well, I do have some advice. , please keep quiet while eating.          A. In all               B. Of all        C. At all           D. Above all 答案：D关于“双受精”，下面的说法正确的是A．是自然界中一切生物所具有的B．是绿色开花植物所特有的C．是自然界中一切植物所具有的D．以上说发均错误