when you use it,you can talk to people,but you can't see them 猜谜

which is black when you buy it,red when you use it,and gray when you throw it away?猜一猜: Which is biack when you buy it,red when you use it,and gray when you throw it away which is black when you buy it,red when you use it,and gray when you throw it away? Which is biack when you buy it,red when you use it,and gray when you throw it away when you use it,you can talk to people,but you can't see them 猜谜 What do you throw out when you want to use it,but take in when you don't want to use it what do you throw out when you want to use it,but take in when you don’t want to use it?怎么回答 it is very ____(use) to you when you study english. 英语翻译When you travel in Brazil ,you can’t use OK signs.It is rude there. （英语谜语）which is black when you buy it,red when you use it,and gray when you throw it away When do you use a computer?英语翻译 can you tell me ( )i can use it.A.what B.when 可以说成：Take care not to break the glass when you use it. 句子结构分析It's necessary for you to lock the car when you do not use it.It's necessary for you to lock the car when you do not use it.necessary 表语you 主语to lock 谓语the car 宾语从句when you do not use it 是什么的补语?这句 which hands do you use when you are writing? The better you use it ,the more you get it . When you're learning English ,use it ,_____you'll lose it . A.but B.and C.t use you head,then think it over