A:What's your name?
B:How are you?
乙型肝炎是由乙型肝炎病毒引起的一种传染病,以下属于保护易感者的做法是( )
用长4厘米、宽3厘米的长方形,照下图的样子拼成正方形.拼成正方形的边长最小是____厘米?