For a form to be usable, all three aspects need to be tackled.

一个好用的表单，需要解决这三个方面的问题。

youdao

They are designed to be usable on slow speed and broadband connections.

它们被设计应用于缓慢的速度和宽带连接。

youdao

Our system didn't have demanding performance requirements, but we wanted it to be usable under peak loads.

我们的系统没有苛刻的性能需求，但是我们想让系统在最大负载下是可用的。

youdao

To be a building, half of a structure's height must have usable floor space.

VOA: special.2010.03.31

But if the aperture is reduced too much, the image may be too dark to be usable.

ECONOMIST: MONITOR

There will be no demand for these free currencies so long as the dollar remains stable enough to be usable as money.

FORBES: Monetary Policy FAQ: Explaining the Basics of the Dollar

The One X snap was too dark to be usable, while you can just barely make out the boat in the Galaxy S III's.

ENGADGET: From the lab: Lumia 920 low-light shootout with Nokia 808, iPhone 5, HTC One X and Galaxy S III