单项选择题
A. He wanted to keep them for further use. B. The deadline just slipped his mind. C. He forgot to take the case where the books are. D. His wife threw the books away with trash.
A. Indifferent. B. Expectant. C. Optimistic. D. Pessimistic.
A. Friends. B. Teacher and student. C. Boss and employer. D. Father and daughter.