undergo的過去式和過去分詞是什麼？

例句：

She later underwent 19 operations.

之後她接受了19次整容手術。

Last year, Ms. Mason underwent surgery.

梅森女士於去年動了手術。

The promising singer underwent mysterious misery.

那位有前途的歌手遭受了神祕的痛苦。

Design itself has undergone deep changes as well.

設計本身了已經經歷了深刻的變化。

I learnt that you had just undergone an operation.

我得知你剛經歷了一場手術。

Her smile had also undergone a transformation.

她的笑容也改變了。