关于电磁场和电磁波,下列说法正确的是 [ ]
A.电磁波是横波
B.电磁波的传播需要介质
C.电磁波能产生干涉和衍射现象
D.电磁波中电场和磁场的方向处处相互垂直
ACD
用括号里所给动词的适当形式填空。注意:每空不限一词。
小题1:In winter birds fly far away ___________(find) a warm and sunny day.
小题2:Yesterday Mr King’s car ____________(break) down on his way home.
小题3:—Hello, who’s that? —Hello, this is Timmy ___________(speak).
小题4:Don’t forget _____________(introduce) our school to Mr. Wu when you see him.
小题5:What __________ he __________(do) from nine to eleven last Sunday morning?
宫颈糜烂的分度依据()。
A.糜烂深度
B.糜烂形状
C.糜烂面积
D.糜烂位置
E.糜烂性质