One difficulty is that almost all of what is called behavioral science continues to trace behavior to states of mind, feelings, traits of character, human nature, and so on.(备注：粗体内容为what引导介词of宾语从句，介词of+what宾语从句 ，修饰all ,然后，all of+what宾语从句一起作that引导表语从句主语。)

参考译文:难题之一在于所谓的行为科学几乎全部仍然是从心态,情感,性格特征,人性等方面去寻找/追溯行为的根源。

all of what is called behavioral science【主语】// continues【谓语动词】// to trace behavior to states of mind, feelings, traits of character, human nature, and so on【宾语】  (特别备注：all of what is called behavioral science为表语从句的主语，continues为表语从句谓语动词，不定式to trace...为that表语从句宾语成分。）

【1】这里what作为关系代词引导定语从句，类似of+what引导宾语从句，what在句中做主语？可以这样表述吗？

解答：正确表述为：what为融合性连接代词/融合性关系代词引导介词of名词性从句(宾语从句)，what=the thing that 同时在宾语从句中作主语成分。

【2】定语从句中，whose表示……的，可以转化为：the+名词+of+which（whom）

那么of which，of whom，of what，这三个情况在句子中遇到之后如何区分？

解答：whose引导定语从句可以转为the+名词+of+which（whom）

We live in a house whose windows face south.=We live in a house the windows of which face south

我们居住在一所窗户朝南开的房子里。

He is the man whose car was stolen.=He is the man the car of whom was stolen. 

他就是汽车被窃的那个人。

比如One difficulty is that almost all of what is called behavioral science continues to trace behavior to states of mind, feelings, ……这句话中的of what可以用of which来替代吗？？

解答：以上what不是引导定语从句，而是引导介词of宾语从句，然后这个主语从句作介词的宾语，不可以用of which替代

【3】She is pleased with all that you have told.这里的that可以省略吗？

解答： that you have told为定语从句修饰代词all可以省略that, all that=what