2 sentences

1. 你的行为反复无常吗？

   nǐ de xíng​wéi fǎn​fù​wú​cháng ma?

   Is your behavior erratic?

   Source: OpenSubtitles

2. 他的脾气反复无常，让人难以捉摸。

   tā de pí​qi fǎn​fù​wú​cháng, ràng rén nán​yǐ zhuō​mō.

   His temper is fickle and unpredictable.

   Source: Dong Chinese Dictionary