Перекладите на англиский (вправа 6), Зарания спасибо

1 what river is the longest?

2 Ann is the shortest among the pupils of her form

3 this book is the most interesting

4 which of the pencils is the cheapest?

5 this task is easier than that one.

6 this boy is the happiest in the world.

7 our school is better than that one.