防盲治盲的"三A"原则（）
A.适当的
B.可接近的
C.多功能的
D.能负担的
E.先进的
参考答案：A, B, D
—How about having a picnic in the park on Sunday?
— ___________ . Whatever you want to do is fine with me.[ ]
A. You're welcome
B. It's boring
C. It's up to you
D. It depends
在一个工作区可以打开的数据库文件数为( )。
A．1
B．2
C．10
D．15
