To clean the water tanks for water heaters located at roof level.什么意思，快

I want to get someone to clean(cleaning) the room, He was made to clean the room ___time 英译中you have the to breathe clean air do you have to clean the room?怎么回答 how to clean trojan ? take these plates away to the kitchen and bring some clean ones,please. The walls look clean.They____? wa l king the sky having suffered such heavy pollution already, it may now be too late to clean up the river. [add to][make the air clean][trace...back...][potato chips][shopping list]什么意思？问题补充还有提