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/...

1) Have people walked on Mars? - No, they haven't. 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 hasn't.