—Mum, my little sister is crying all the time. —Mary, be         ! She feels sick. You should take good care of her.

Yang Shanzhou becomes well-known in China for planting so many trees for people.

John is my _____friend of all the classmates.

This book is very _____ and I am ______ in it.

The students are too _____ to keep their eyes open in class because of staying up late.