________ students are in the classroom.
There ____ lots of bad information that is not suitable for teenagers on the Internet.
Listen! David is talking happily with his mother in the next room. — It ______ be his mother. She has gone to Yunnan to be a volunteer doctor.
Why are you so late?—I was in half the way when it______to me that I had left my notebook home,so I had to fetch it.
Father some bread for breakfast this morning.