做完了OG11的SC，对于that的用法比较迷惑。 1）对于that的省略： 5.As its sales of computer products have surpassed those of measuring instruments,the campany has become increasingly willing to compete for the mass market sales it would in the past conceded to rivals.为什么sales后面的that可以省略哪？同理： 54.When Congress reconvenes,some newly elected members from rural states will try to establish tighter restricitons on the amount of grain farmers will be allowed to grow and to encourge more aggressive sales of United States farm products overseas.为什么farmers前的that可以省略？ 2）对于that的替代用法，that在一般情况下是可以替代who和which的，为什么以下情况不可以？ 64.The technical term "pagnination" refers to a process that allows editors,rather than printers,to assemble the page images that become the metal or plastic plates used in printing. D.refers to a process which allows editors,rather than printers,to assemble 语法点里的介绍which和that在这种情况下应该是可以替换的吧？ 130.As a result of medical advances, many people who might have died in childhood of such infections as diphtheria,pneumonia,or rheumatic fever now live well into old age. OG的解释为the pronoun who,rather than that,should be used to refer to people.但在一般语法书里，who和that在此用法应该是可以互换的吧？ 这是我对OG11的SC的that用法不明白的总结，相信一些cder也会有这样的迷惑，希望NN们给我们这些菜鸟一些解答，谢谢！！  | 
