dip one's toe into (或 in)

put one's toe briefly in (water), typically to check the temperature

（尤指為了試溫度）將腳趾在（水）中蘸一下

dip out

(Austral. informal)fail

(澳，非正式)失敗

I nearly dipped out of the course.

我?guī)缀醢胪径鴱U。