– I’m leaving for Beijing next week.
– How long there?
A. have you stayed
B. are you staying
C. had you stayed
D. did you stay
网友回答
A. have you stayed
(答案→)B. are you staying
C. had you stayed
D. did you stay
解析：考查将来时表达法。本题使用现在进行时表示将来时。现在进行时代替将来时表示事先计划好，安排好的事情；而且动词是表示位置变化移动的动词。句意：—我下周去北京。—你要在那里待多久？根据句意说明是事先计划好的事情。故B正确。