家畜最常用的，用量最多的能量饲料是玉米。（）
参考答案：对
为何跨膜糖蛋白的糖基总在细胞膜外表面？
—Is ______ your dictionary?
—Yes, thank you. And ______ are my books. [ ]
A. this; this
B. this; these
C. these; this
D. these; these
