What he wanted to know the pay, the living and workingconditions, and the kind of job he would be assigned.
为何这个选were 而不选was ?
第一要说明的是，你的句子用单数也完全可以的。
What 从句一般被觉得是单数的，其后谓语动词用单数。如：
What we want is money. 大家想要的是钱。
What he wants is a better job. 他要的是更好的工作。
What we want is some straight talk. 大家想要开诚布公地谈一谈。
What we want is a home of our own. 大家所想要的是一个大家我们的家。
What they want boils down to just one thing. It island. 他们说穿了就是想要一样东西，那就是土地。
What we want is a car that’s cheap and reliable. 大家想要的是一辆价格实惠、性能靠谱的汽车。
但假如其后接的表语是复数，则也可以用复数动词（但同时也可以用单数动词）。如：
What we want is / are more textbooks. 大家需要更多的教程。
What he wants is / are two double room. 他想要的是两个双人间。
What we want is / are some of those cakes. 大家要一些那样的蛋糕。
请看PEU的有关说明：
