从A、B、C、D四个选项中.选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。
21.【2012•西安一次质检】He was poorest man here years ago, but now he is rich man.
A．a; the B．不填; the C．the; a D．不填; a
22.【2012四川卷】—Did you catch what I said?
—Sorry. I ______ a text message just now.
A. had answering B. have answered C. would answer D. was answering
23.【2012届宁夏银川一中高三第六次月考试题】 Passengers are permitted _____ only one piece of hand luggage onto the plane.
