旅客购买卧铺票时，必须要有（）票。
A.加快票
B.附加票
C.空调票
D.软座或硬座客票
参考答案：D
一切正在发声的物体都在______，用手按住正在发声的锣面时，由于锣面停止______，锣就停止发声了．
根据首字母填空完成句子。
1. Plants can't live without l_____.
2. The poor cat d_____ beside the street yesterday.
3. There are sixty s_____ in a minute.
4. Yuan Longping is one of the greatest s_____ in China.
5. She said it in a w_____, so I couldn't hear her well.
