多媒体技术基础是()、人机交互方法及设备的改进。
A、大容量存储设备
B、数据压缩技术
C、高速处理器
D、高速通信网
参考答案:A, B, C, D
小华今年X岁,小明今年(X-b)岁,再过a年,两人相差( )岁.
A.a+b
B.b
C.x+b
D.x-b
The house could fall down soon if no one ______ some quick repair work.
A. has done
B. is doing
C. does
D. had done