Both clay and sandstone are unstable rock formations.黏土和砂岩都是不牢固的岩石构造。

After the fall of Pitt in 1801 there was a decade of unstable government.1801年皮特倒台后, 政府经历了10年的动荡。

The situation is unstable and potentially dangerous.情况不稳定, 可能有危险。

Coleridge was a highly unstable person.柯尔律治是个非常情绪化的人。