He is so careless that he often_______his schoolthings at home.

n the two periods of classes is a break, _______we can have a short rest.

By reading the article, we know how ______ in ourdaily life.

The police set about arresting the suspect ______ they found enough evidence to prove him guilty

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