help me ,please.1.no bread eaten by man is so sweet as that earned by his own labor 为什么用that?one 或 what 为什么不行?2.you can not imagine the hard time he had holding the horse in为什么用holding?怎么翻译?3.I have kept the portrait where I can see it every day,as it always remind me of my university days in London 为什么用where?in which为什么不行?4.it is quite warm today for january.为什么用for?怎么翻译?

1. that 做从句主语，what不行，one 是特指某一事物，这里也不是。
2.后面应该还有句子，你不写出来 我只能断句在 had 和holding 之间了 至于holding 就是坚持的意思了 你要和后面联系起来理解
3.keep in 是一词组 意为 隐瞒, 隐藏，在这里讲不通
4.现在的天气对于一月来讲太暖和了。 for 这里做介词 和。。。比较的意思

1. 比较代词，单数用that，复数用those
2. hold in 约束，抑制
3. where 这里等同于in which place 而不是in which
4. 根据句子语气可知，这里有个比较的意思在里面，用in说不通，而其他介词中符合的只有for，be+adj+for 固定搭配

1.no bread eaten by man is so sweet as that earned by his own labor 为什么用that?one 或 what 为什么不行?首先,bread是不可数名词,用one肯定是不行的.其次,这是一个定语从句,如果还原为正常语句应该是:No bread...