I believe _____ important to have a rest when you feel very tired. 

—Are these books yours, Mike?—No, they aren’t. They belong to ______.

—______is the Changjiang river in China, do you know?—Yes, it’s about 6,380 kilometers long.

 Does our headmaster have _______________ to tell us?

There are two dogs in my family. One is white,_____________ black.