下列句子没有语病的一项是

Paul doesn’t know _________ about his problems.

Where ______________ – An art exhibition. I think it’s really worth _______and we can learn a lot from it.

填入下面横线上的两句话，与上下文衔接最恰当的一项是( )泰山的南天门又叫三天门，创建于元代，至今已有六百余年。________，为“门辟九霄仰步三天胜迹，阶崇万级俯临千嶂奇观”。

Mary couldn’t________ the terrible working conditions in that factory and resigned last week.