1. It/take/about 30 minutes/do/exerscise
--> It takes about 30 minutes to do the exercise
2. I/used/go/work/bike/when/i/be/child
--> I used to go to work by bike when I was a child
3.He/go/picnic/friend/last summer
--> He went to picnic with his friend last summer
4. We/reduce/use/electricity/save/our energy
--> We reduce using electricity to save our energy.
5. At 10 pm next month,we/visit/grandparents
--> At 10 pm next week, we will be visitng our grandparents
6. You/turnoff/lights/before/go/out
--> You should turn off the lights before you go out.