Question

it is by no means clear what the president can do to end the strike. 怎样翻译，为什么用what？

Answer 1

楼下翻译得不全。 by no means clear = certainly not clear 不确定
It is certainly not clear what the president can do to end the strike.
尚不确定总统能采取何种方式结束此次罢工。

that与what都可引导主语从句，that在从句中不作句子成分，但不能省略。
what 在从句中可作主语、宾语、表语等，不能省略。
这里what作从句里的宾语“ the president can do [what] to end the strike."

如果这句的从句部分有自己的宾语，例如，
the president can do [anything] to end the strike
那这里就需要用that引导，
It is by no means clear that the president can do anything to end the strike.

Answer 2

总统能做些什么来结束这次罢工。

这道题正解是 what .
句中it 是形式主语， 真正的主语是后面的句子
the president （ 主语） can do （ 谓语） to end the strike （动词不定式短语作 目的状语）， 根据以上分析 很显然句子谓语can do 后少宾语， 故主语从句连接代词用 what