题目

You're the only person ______I've ever met ______could do it. A. who;/               B./; whom          C. whom;/          D./; who   答案：D构成动物细胞膜的主要成分是（ ）A.脂质B.蛋白质C.脂质和蛋白质D.蛋白质和核酸