No one knows how long it will last.

谁也不知道会持续多久。

youdao

The relationship between the amount of light an incandescent bulb can produce and how long it will last is complicated, to say the least.

退一步说，一盏白炽灯能产生的亮度与其照明寿命之间的关系很复杂。

youdao

Even if managers know that a new product will follow this cycle, they cannot be sure when each phase will start and for how long it will last.

即使管理者们知道一个新产品要经历这个周期，他们也无法确定各个阶段将会于何时开始，以及将要持续多长时间。

youdao

Dollet adds that while there are other Arabic-speaking countries that do not control the Internet as much as Egypt, it is not clear how long that relative freedom will last.

VOA: standard.2009.11.16

The formal investigation is ongoing, Lombardi said Monday, refusing to comment on how long it will last.

CNN: No cardinal suspected of pope papers leak, Vatican insists

How long it will last, what the complications will be, and how likely it is to kill you.

FORBES: Gene Tests That Predict When You Will Die

It's just not clear how long it will last at home or abroad.

NPR: Obama Must Manage Great Expectations