The thought of going back home was all that kept him happy while he was working abroad.这句话当中的all做什么成份（可否省略）又怎么解释?

We thought of going to the cinema.翻译下` thought of the he thought he was going to be Person of the Year in 1984,请帮着翻译, THE SPEED OF THOUGHT怎么样 THE GEOGRAPHY OF THOUGHT怎么样 she thought of the Chicago He was ___ to stay in the small town that he never thought of going to somewhere else. I thought the fight was going to take a lot out of me.这句话怎样翻译. At the thought of the disaster the thought of you,heart pain THE EVOLUTION OF EDUCATIONAL THOUGHT怎么样 THE FOUNDATIONS OF MODERN POLITICAL THOUGHT怎么样 the thought of going back home was ______kept him happy while he was working aboard 这里为什么不能用WHAT 只能用THAT The thought of going back home was all that kept him happy while he was work.先行词是什么?that能不能用which? The thought of going back home was ----------kept him happy while he was working abroadA thatB all thatC all what D which请说明理由 We were lost in thought,so we wrer not aware ---was going on aroundA what B of what Cof the thing D that I thought I was going to fail the exam,but I passed ____Aabove all Bafter all Cin all Dfirst of all 宾语从句,the thought of going back home was ___ kept him happy while he was working aboradAthat Ball that Call what Dwhich选什么呀,为什么呢?