They can change from clear to dark and black again when people touch them.

人们触摸时，它们会从透明变成深色，再变成黑色。

youdao

You can see a clear line where the black rock becomes white.

你可以看到一条清晰的线条，在那里黑石头变成了白色。

youdao

E Ink is based upon tiny capsules filled with positively charged white particles and negatively charged black ones, suspended in a clear liquid.

电子墨水[技术]基于微型胶囊，该胶囊填充有带正电荷的白粒子与带负电荷的黑粒子，悬浮在透明液体中。

youdao

Professor Robinson says it is not clear when the first marriage between a black person and a white person took place.

VOA: special.2010.09.03

The black line makes it clear that gigabyte shipments barely deviate from the trend.

FORBES: The Role of Demand in Semiconductor Forecasts

This is how a CRM system succeeds: with a clear, black-and-white deliverable.

FORBES: The Secret To Successful CRM

The Black Cats failed to clear a free-kick and Behrami latched on to the loose ball to drive a shot from inside the box that deflected off Jones and into the net.

BBC: Sunderland 0-1 West Ham