It never rains but it pours 祸不单行
The Wimbledon Championships, held since 1877, is one of the most prestigious tennis tournaments in the world. Wimbledon traditions include a strict dress code for competitors, the eating of strawberries and cream by spectators, and the presence of members of the Royal Family. Wimbledon's Centre Court was fitted with a retractable roof to lessen the loss of playing time due to rain.
“不雨则已，一雨倾盆”，形容坏事不来则已，一来则不止。It never rains but it pours 和中国成语里的“祸不单行”意思一样。
We had nothing to do for weeks, then suddenly we have all this work to do; it never rains but it pours!
I missed my train this morning, lost my wallet and spilt coffee all over myself; it never rains but it pours.
如果你给某人的计划或建议“泼冷水” pour cold water, 那就表示你的态度是太过苛刻或消极。
I wanted to walk up the mountain but Jane threw cold water on the idea by taking the cable car.