English Translation
I gave all of the Chinese proverbs back to the teacher.
还给老师 (idiomatic) to forget everything one has learnt
我发现我的英语都还给老师了。
Wǒ fāxiàn wǒ de Yīngyǔ dōu huán gěi lǎoshī le.
I found out that I have forgotten all the English I have learnt.