We enjoyed the picnic until a thunderstorm intervened.

那次得很痛快, 后来一场暴风雨使它中断了。

THUNDERSTORMS are notoriously unpredictable, as many a drenched picnicker can attest.

雷暴难以预测，对此那些被淋得透湿的者深有体会。

Thunderstorm is common in summer.

雷电交加的暴风雨在夏天很常见。

Clouds gather before a thunderstorm.

在风暴来临之前云层聚集。