They are firefighters 改为单数 What do you do ? 回答

Everyone here will thank the firefighter for the things they have done to prevent fires______the environment safer.A.make B.to making C,to make D.from making 非谓语动词选择题,请详解.Everyone here will thank the firefighter for the things they have done to prevent fires and ______ (make) the environment safer . volunteer-firefighter什么意思急 They are they are Are they They are -------are they?they are --------(tomato) firefighter和 fire brigade有什么区别? 一道不会做的英语选择题……Everyone here will think the firefighter for the things they have done to prevent fires---the environment safer.我选的是from making make 为什么呢啊?求赐教 --Are they ( ) buuks?No,they are not .--They are ( ) buuks. They are green.They are long.They are g( ) b（ they are food.they are long.they are white.谜底 are they,do they 区别 Are they horses?They are__________ Are they ( )skating?Yes,they are. they are who they are.怎么翻译? where they are 和where are they