Most people sleep at night, but Frank sleeps during (在……期间) the day and works at night. His work is to guard（守卫） a big ____. Frank likes his work. He knows that it is ____ to guard the building at night. If he hears any noise, he goes ____ to see what it is. Most of the time he walks around inside the big building, but he also walks around outside. When he is ____ he can sit on a chair by the door (门). It is very cold in winter. He always ____ a warm coat when he is working.

    Frank used to feel lonely (过去感到孤独) because no one ____ with him in the evening. One night when Frank was walking outside, he ____ a noise. He went very quietly to the noise to see if someone was there, ____ he only saw a small dog. Frank talked to the dog. It ____ cold. He took the dog inside the building, and the dog followed ____ around happily.

    Now Frank is not lonely. The dog is his good friend.