undergo的过去式和过去分词是什么？

例句：

She later underwent 19 operations.

之后她接受了19次整容手术。

Last year, Ms. Mason underwent surgery.

梅森女士于去年动了手术。

The promising singer underwent mysterious misery.

那位有前途的歌手遭受了神秘的痛苦。

Design itself has undergone deep changes as well.

设计本身了已经经历了深刻的变化。

I learnt that you had just undergone an operation.

我得知你刚经历了一场手术。

Her smile had also undergone a transformation.

她的笑容也改变了。