有的单糖既能构成二糖又能构成动物或植物特有的多糖。下列单糖中，具有上述特点的是：[ ]
A．葡萄糖
B．果糖
C．核糖
D．半乳糖
答案：A
初等义务教育普遍实施于近代。( )
The visitors _______ our school in two days. [ ]
A. came to
B. will come to
C. come to
D. has come to
