How long is he staying?

他要待多久？

youdao

How long is he staying? He is staying for a week.

他准备在那呆多久？他准备在那呆一周。

youdao

How long is it since he left this school?

他离开这所学校有多长时间了？

youdao

The senior executive is worried about how well-positioned he is for the next CEO job, while the employee is worried about how long he will be able to keep his job.

FORBES: The Great Divide In Corporate America: CEOs and Employees

For that is how long he has been dominating the Irish chat show, on television and radio.

ECONOMIST: An Irish guru to go | The

It is not clear how long he had been in Nicaragua.

BBC: Eric Justin Toth