亚洲激情+欧美激情,无码任你躁久久久久久,我的极品美女老婆,性欧美牲交在线视频,亚洲av高清在线一区二区三区

電子課本網(wǎng) › 第122頁

第122頁

信息發(fā)布者：
Weather comes from the earth's atmosphere and the sun's heat.
Air.
Hot air rises, leaving a space behind.Cooler air goes into that space.
The water vapour in clouds cools and becomes raindrops.The raindrops get bigger and heavier 
until they fall from the cloud.
If the temperature is below freezing,tiny bits of ice called crystals form in a cloud.When ice crystals 
fall and stick together,they become snowflakes.
D


B

D
上一頁 下一頁