题目

 Please remain ____ until the plane has come to a complete stop. A. to seat                    B. to be seated                    C. seating                    D. seated 答案：D下列5种有机物：①2-甲基丙烷；②乙醇；③丙烷；④丁烷；⑤葡萄糖。按它们的沸点由高到低的顺序排列正确的是（     ） A．①②③④⑤                           B．⑤②④①③ C．⑤④②①③                           D．③①②⑤④