用所给短语的正确形式完成下列句子

【小题1】He realized that she was crying _______________what he had said.
【小题2】Boys ____________John and James are very friendly.
【小题3】While we were talking, a young man _____________________.
【小题4】We should train them to ____________reference books.
【小题5】No one can help us with our work ________.
【小题6】This song ____________an old love story.