Someone is knocking at the door.- It ______ be Tom. He is still in the school.

I knocked on the door several times but answered, so I left.

Look! The clouds are red and orange. They are so beautiful.–Yes. They show it will be sunny tomorrow.

Bob is ________ at the map to find where Beihai Park is.

Is the blue ruler _______? —No. _______ ruler is red.