I was about to leave the office ______ an unexpected visitor came.A. while B. as C when D. before
Because of ______high demand for Type AB blood,____supplies of it are usually limited.
His parents never approve of_____ he plans to do, which always annoys him.
According to the school rules,no student _________go out of the school after eleven o’clock at night without the teacher’s permission.
According to statistics, a man is more than twice as likely to die of skin cancer _____a woman.
---What kind of house would you like? ---I’d like____ with a swimming pool at the back of ______.