问题
选择题
All passengers _______, please fasten your seat belts and remain seated _______ the plane is landing.
A．on board; until
B．abroad; since
C．on the board; before
D．aboard; when
答案
答案：D
题目分析：句意：所有机上的乘客，请系好安全带，当飞机着陆额时候仍然要坐着。on board 在此处相当于aboard，表示"在飞机上"。第二个空填when，指当飞机着陆的时候。选D。