出没无常 出沒無常

    chūmòwúcháng

    1. Verbto appear and disappear unpredictably

    那只狐狸在森林里出没无常,很难被人发现。Nà zhī húli zài sēnlín lǐ chūmòwúcháng, hěn nán bèi rén fāxiàn.The fox in the forest appears and disappears unpredictably, making it hard to spot.