无敌小雷神
很难估计这次旅行要花多长时间。
It's difficult to judge how long the journey will take.
你原打算待多长时间?
How long a stay did you have in mind?
你干现在这工作多长时间了?
How long have you been in your present job?
我正要出去,用不了多长时间。
I'm just going out ─ I won't be too long.
你做家庭作业用了多长时间?
How long did you spend on your homework?
sherryaigigi
多长 How long is.....?多宽 How wide is....? 如果你想问某物品的尺寸,长宽高之类,就问What's the dimension of...?