Chinese phrase
要多长时间？ yào duō zhǎng shí jiān
Meaning
How long will it take?
When to use it
Asks how much time something will take. It is a neutral way to ask about the time needed for an action or task.
Example dialogue
写完这份作业要多长时间？ xiě wán zhè fèn zuò yè yào duō zhǎng shí jiān
How long will it take to finish this homework?
大概二十分钟吧。 dà gài èr shí fēn zhōng ba
About twenty minutes, I think.