— What time shall we leave for the airport? — It's foggy today. I'm not sure __________ be closed soon. Let's go now.
A:whether the highway wil
B:whether will the highway
C:when the highway will
D:when will the highway
下列各图中,可以是一个正方体的平面展开图的是( )
打开收音机的开关,将旋钮调到没有电台的位置,并将音量开大.取一节干电池和一根导线,靠近收音机将导线的一端与电池的一极相连,再用导线的另一端与电池的另一极时断时续的接触,会听到收音机发出“咔咔”声,这一现象说明周围的空间存在( )