Make questions, then work with a friend and ask and answer
1.walked/Mars /on/people /have?
2.the /has/changed/climate?
3.we/environment/the/have/ protected?
4.pollution/trees/has/a lot of/destroyed?
5.stayed/the/has/same/world/the ?

1) Have people walked on Mars - No, they havent.
2)Has the climate changed - Yes, he has.
3) Have we protected the enviroment Yes, we have.
4) Has pollution destroyed a lot of trees - Yes, it has.
5) Has the world stayed the same - No, it hasnt.