题目内容
【题目】下列关于声音的产生和传播说法正确的是（ ）
A．物体不振动也可以发出声音
B．空气不能充当传播声音的介质
C．声音在真空中的传播速度为340m/s
D．音调与声源物体振动的快慢有关
【答案】D
【解析】
试题分析：声音是发声体振动产生的，一切发声的物体都在振动；
声音的传播需要介质，它既可以在气体中传播，也可以在固体和液体中传播；
声音的高低叫音调，音调与发声体振动的快慢有关，振动越快音调越高．
解：
A、声音是发声体振动产生的，物体不振动不能发出声音，此选项错误；
B、固体、液体和气体都可以作为声音传播的介质，声音可以在空气中传播，此选项错误；
C、声音传播需要介质，真空不能传声，此选项错误；
D、音调与声源振动的快慢有关，振动越快音调越高，此选项正确．
故选D．
【题目】
until | glad | when | kind | invite | surprise | catch | guest |
Having a surprise party is very popular,Most peo1ple are 【1】 to have a surprise party for their family and friends. Do you know what a surprise party is like? Let me give you an example.
It was half past six in the evening.Bob 【2】 his father Mr. Green to his bedroom to play chess.【3】 Mr.Green opened the door, he found the room was dark.Suddenly (突然) a lion 【4】 him.He was a little afraid.Then the light was on. He found the lion was Bob! Behind Bob, Mr.Green saw his wife and some 【5】.All of them said to Mr.Green, “Suprise!?” Mr.Green was confused(迷惑的). He didn't know what it was 【6】all of them said“Happy birthday”to him.
There are different 【7】0f surprise parties. But a successful surprise party always makes pcople feel 【8】and happy.