there a lot of rubbish on the floor so i asked maer to sweep upa were it b are them c was it d is them

there a lot of rubbish on the floor so i asked maer to sweep up
a were it b are them c was it d is them

C
asked,所以是过去式　垃圾不可数,所以用was

选C， rubbish不可数。用it作替代，代词放在词组sweep 和up 中间