【判断题】波长和频率的关系是,频率越高,波长越长,频率越低,波长越短。
【单选题】Which of the following statements on the 30 people on board is CORRECT?
B.
They were all rescued by a helicopter.
C.
Some of them were rescued by fishing boat.
D.
It was not mentioned in the news.
【简答题】Many people were watching the match yesterday afternoon. There were many people ______ the match yesterday afternoon.
【单选题】On December 26, 2004, a terrible tsunami happened in the Southeast Asia, _________ many people.
【单选题】关于长波、中波、短波的下列说法中正确的是 [ ]
【单选题】频率、波长、波数及能量的关系是______。