防止病邪侵害属于
A．因时制宜B．未病先防C．因人制宜D．因地制宜
参考答案：B
He had a wonderful childhood, _____ with his mother to all corners of the world. [ ]
A. travel
B. to travel
C. traveled
D. traveling
字长是计算机的一个主要性能指标，字长越短，计算机的运算速度和效率就越高。( )
