有序元素对相等的映射是一个()。
A. 散射
B. 不对等映射
C. 不完全映射
D. 单射
Φ(N)是欧拉函数,若N>2,则Φ(N)必定是偶数。()
A. 对
B. 错
The little girl was glad to see that the basket was filled ( ) apples.
A. off
B. in
C. on
D. with
She has won many awards, and has even written a book about her experiences in ( ) English.
A. learning
B. learn
C. learned
D. learnt