1. we will plant more trees. The air will be fresher.

=> If we plant more trees, the air will be fresher.

2. WE will use fewer cars. WE will reduce pollution.

=> If we use fewer cars, we will reduce pollution.

25.If we plant more trees, the air will be fresher.
26. If we use fewer cars, we will reduce pollution.
28. tallest / my / is / the / family / in / brother/ person / my. (Rearrange the words to make meaningful sentences.

→  My brother is the tallest person in my family.

29.visited / We/ our grandparents/  in the countryside / last week.(  Rearrange the words to make meaningful sentences.

→ We visited our grandparents in the countryside last week

25.We will plant more trees and the air will be fresher.
If we plant more trees, the air will be fresher.
26.We will use fewer cars and we will reduce pollution.
If we use fewer cars, we will reduce pollution.
27. I had a bad cold, so I didn’t go to school yesterday.  (Rewrite this sentence with “because”)
I didn't go to school yesterday because i had a bad cold.
28. tallest / my / is / the / family / in / brother/ person / my. (Rearrange the words to make meaningful sentences)
My brother is the tallest person in my family.
29.visited / We/ our grandparents/  in the countryside / last week.(  Rearrange the words to make sentences)
We visited our grandparents in the countryside last week.