I am waitingto take you to the station.英语句子划分成分，

Question

I am pleasend to be invited to talk here，句子划分 I 是主语 其他的做什么成分
Nell went away only to leave his two children by themselves .句子划分
To hear the professor clearly ,I chose to be seated in the front.
I t is our duty to take care of the old.

Answer 1

am 是系动词， pleasend 是表语 I am pleased 构成主系表结构，to be invited 是被动语态，to talk 是前面be invited 的补语

Answer 2

i am please为主系表结构，to be invited to talk here是不定式作原因状语
nell went away是主谓结构，only to leave his two children by themselves为结果状语
to hear.... 为目的状语，后句是主句部分
it is our duty中的it为形式主语，代替to take care of the old

Answer 3

I am pleasend to be invited to talk here这句话里不定式里还有不定式，
一：I 主语，am系动词，pleasend 表语，to be invited to talk 不定式作表语补足语，here状语
二：I 主语，am pleasend 动词短语，to be invited to talk 宾语，here状语
三：第二个to talk 作为invited的补语，或看做be invited的宾语
解释：有的语法家认为 am pleasend 有动词的性质。我们经常看到的是英语的 “be+形容词”结构后面接的都是非动词，一旦接“动词”了，都被非谓语化了，所以完全可以把be+形容词归类为动词的。be busy doing sth/be hard to do ，easy to solve the problem等等。这样类似的很多。所以am pleasend 可以看做是动词的。
四：nell went away是主谓结构，went为不及物动词作谓语，away是副词作状语only 是副词修饰不定式，to leave his two children 不定式作结果状语，by themselves 介词短语作状语
to hear.... 为目的状语，I chose 主谓，to be seated in the front.不定式作宾语
it is our duty中的it为形式主语，代替to take care of the old ，to take care of the old 作主语