We must keep the air clean and never _________ (pollute,polluting) it.

We must keep the air clean and never _________ (pollute,polluting) it. We must keep the air in the room clean.(改为被动语态）The air in the room must ＿＿ ＿＿ clean. the earth is our home.we must ___the land,air,and water clean.为什么是keep而不是get we must keep the ( )on the road we must keep the( ) on the road 改错 We must keep the classroom cleanly. We must ___(keep) the classroom clean. We must keep the window______(open). we must keep( ) in the hospital we must keep the reading room quietly还是we must keep the reading room quiet we should keep the air ___ ___ ___ (清新) 单项选择The earth is our house.We must _____ the land,air and water clean.A .change B.let C.stay D.keep keep the air frsh we must keep the balance of ( ).(自然界)填正确形式 同意表达we must keep quiet in the library we must put rubbish bins and keep the environment oceans we keep must the clean.怎么连词成句. we must keep quiet at the library错误在那里