乌云

空中kōngzhōng有yǒu一yī大片dàpiàn乌云wūyún。

There is a mass of dark clouds in the sky.

乌云wūyún逐渐zhújiàn布满bùmǎn了le整个zhěnggè天空tiānkōng。

The sky has gradually clouded over.

乌云wūyún是shì下雨xiàyǔ的de征兆zhēngzhào。

Dark clouds are a sign of rain.

天空tiānkōng突然tūrán变得biànde乌云wūyún密布mìbù。

Suddenly, the clouds darkened the sky.