1.It was recognized that food contained protein。这是形式主语句吗？如果It指代的是上文中的某一件事或某一件东西，那还是形式主语句吗？ that food contained protein位于recognized后，可以是宾从吗？
2.He went a step further in recognizing that he was looking for a strategy。这句话中的that引导的是宾语从句吗？recognizing不是动词了啊
3.一个名词可以跟2个定语从句吗？eg:It is the question that he asked that makes me angry.这句话对不对
4.Experts say that one of the ways that job seekers can stay safe is to conceal their identities。这句话中第二个that引导的是什么从句？如何分辨的？
5.It applies to traditional historians and to social science。这句是简单句还是并列句？有2个动词以上的是并列句还是有2个主语以上的是并列句？网上说法不一
It was recognized that food contained protein。这是形式主语句 it是形式主语 that从句是真主语 It不可能指代上文中的某一件事或某一件东西，因为如果如此 语法不对 应该用主动语态 that food contained protein位于recognized后，这里不可以是宾从因为 主句谓语是被动语态
2.He went a step further in recognizing that he was looking for a strategy。这句话中的that引导的是宾语从句 作动名词recognizing的宾语 动名词具有动词特征 可以带自己的 宾语
3.一个名词可以跟2个定语从句但 须并列
:It is the question that he asked that makes me angry.这句话如果不是强调句型 应该 把 第二个that去掉 he asked改成 he thought 是插入语 也可以去掉
It was the question that he thought made me angry.这样的句型 不属于 两个定语从句
如果 不去掉 第二个that 原句 则是 强调句型 也不属于 两个定语从句
It is the question that he asked that makes me angry
= the question that he asked makes me angry
对主语the question that he asked 强调 不过时态有点问题。
4.Experts say that one of the ways that job seekers can stay safe is to conceal their identities。这句话中第二个that引导的是定语从句 修饰 one of the ways这里 that=in which
say 后面是宾语从句
one是宾从中的主语 is 是宾从中的系动词 to conceal their identities是宾从中的表语。
5.It applies to traditional historians and to social science。这句是简单句
有2个动词以上的不一定是并列句 因为是并列谓语
有2个主语以上也不一定是并列句 因为是并列主语
简单句的定义 是 有一个主语或并列主语 一个谓语或并列谓语 组成的句子 是简单句
1.那就是说it +被动+that这种句型都是形式主吗？
2.a step是宾语，further是状语？in之后作in的宾语，that又作recognizing的宾语，对吗？
3. 句中改为question that he thought that he asked，这样修饰question可以吗？
4.that在句中是什么成分？定从中in which不是=where吗，
it +被动+that这种句型都是形式主
2.a step是宾语，后面整个是 形容词短语 作定语 修饰 a step
further是形容词 后面是 介词短语 作状语 修饰 形容词
in是介词 后面是 动名词短语 作介词宾语
recognizing是动名词 后面是 that引导的宾语从句 作动名词的宾语
原句=.He went a step which was further in recognizing that he was looking for a strategy
3. 句中改为question that he thought that he asked，这样修饰question不可以
应该是 the question that i thought he asked其中 i thought 是插入语 可去掉
如果 你一定要 两个定语从句 修饰 一个名词 我可以 随便 举个例子
this is the book that helps me a lot and that i like best.
4.that在定从中是作方式状语的 =in which 也就是 in the ways
先行词是 the way 并且 在定从中 作方式状语时 有三种引导方法 1 that2in which 3省略关系词
采纳我的吧，本人英语专业，有过之处，还望指正：
判断是不是形式主语，只要把从句放在前面看看句子是不是就可以了。 that food contained protein was recognized，是正确的。因此it就是指that food contained protein。这个叫做同位语从句。宾语从句在整个句子必须有主语，如果that food contained protein是宾语从句，作为整个句子的宾语，那么It was recognized that food contained protein，那您认为主语是什么呢？？前面说了It是形式主语，真正主语是that food contained protein。
如果句子是：we recognized that food contained protein. 宾语从句就是相当于一个名词，这个名字的主语就是we.
这个句子主语是he，went in recognizing属于谓语，a step further不是宾语，是状语表程度。那宾语自然就是that引导的名词性从句，叫做宾语从句。
一个名词可以跟2个定语从句吗？ 理论上可以接两个定语从句,也有例外。
I know the workshop that provides bad goods and whose onwer is dead.
I know the workshop that provides bad goods and that cheats kids.
如果引导词都是that，您觉得还有必要吗？为什么不说:
I know the workshop which provides bad goods and cheats kids ?
在英语中有个规定：并列性质的从句，第二个不能写that.
He told me that the workshop owner was a bad gay and that he was dead.第二个that绝对是多余的。
您的句子第一个that是引导定语从句，第二个是it is ***that***的强调句。
That 引导定语从句，下面这个句子熟悉吧。that 和which的转换 that=in/on/by which
He didn’t like the way that (=in which ) she speaks to his mother。
that 也可以省略掉：He didn’t like the way she speaks to his mother
只要记住这三种用法就可以了：way that +从句，way in which+从句,way+从句
但是He didn’t like the way how she speaks to his mother,
这个句子是错误的，how不能引导定语从句。
简单句：就是没有从句的，不能再分为两个句子的 句子；
并列句：其实里面有两个句子；
复合句：必须含有从句；
区分简单句和并列句的最简单方法就是查看 and 到底是链接了什么和什么，是不是两个句子。
It applies to traditional historians and to social science。and 链接的是to traditional historians和to social science，链接的是两个短语，不是两个句子，因此是简单句。
He went to bed early and felt very tired 是简单句还是并列句呢？？
and 连接的是early 和felt ？肯定不是的。那是连接went to bed early 和 felt very tired两个短语？也不是。and 链接的是He went to bed early和He felt very tired 两个句子，只不过第二句went 和felt 是同一个主语，因此省略了第二个he。这个要注意额。
楼主学习语法只要按序先看懂这以下三章语法，英语自然会有一个质的飞越。
1).名词性从句（The Noun Clause）；
2).定语从句（The Attributive Clause）；
3).状语从句（The Adverbial Clause）；
祝您英语学习名列前茅！ 呵呵。。