vt rõ số mũ đc ko, vt lai giùm mh nha

Rewrite the sentences

1/Keeping the environment clean is very important

->it's

2/They will show the time machine to the public when they finish

->the time machine

3/ He was delighted that

->he was delighted that

4/They are painting the living room yellow

->the living room

5/When does he usually do his homeworld?

->when

6/She advised me to reuse milk bottles

->I