I don't know what to do next.

我不知道接着该做什么了。

《柯林斯英汉双解大词典》

I have got to organize the school clean-up day, but I don't know what to do.

我不得不组织一次学校的清扫日，但我不知道该做什么。

youdao

I don't know what to do.

我不知道该怎么办。

youdao

We leave you with "I Don't Know What To Do" from Pete Yorn and Scarlett Johansson.

VOA: special.2009.10.09

I don't know how to turn it on, I don't know what to do.

我不知道怎样打开，不知道要做什么。

麻省理工公开课 - 媒体、教育、市场课程节选

I don't know. Everyone asks me what I want to do.

我说不准。人人都问我想做什么。

梦想成为时装设计师 - SpeakingMax英语口语达人

"I'm so upset I don't know what to do, " he says.

CNN: Warning -- this garbage is dangerous

Yet on the face of it, there is precious little that is new about The White Stripes' music, with a repertoire that includes Dolly Parton's Jolene and the Bacharach and David standard, I Just Don't Know What To Do With Myself.

BBC: The White Stripes: Raw Rock Revivalists

Ms. GAIL KURTGUARD (Resident, Colorado): If he doesn't get the nomination, I don't know what I'm going to do.

NPR: GOP Faithful in Colo. Reflect Test Ahead for McCain