Why didn’t she ask for help at that time?— You know, at such a midnight, there was no one ________.

The river smells so terrible! How did it come about?—People used to pour dirty water into it.

Susan thought ____not easy to answer all these questions.

I hate those ________ don’t help others when they are in trouble.

Who is that man in black? — He is _______ art teacher in our school.