主语宾语表语的变化
名词、代词
The process is natural selection
But most law graduates never get a big-firm job
They financed them
非谓语动词doing
是动词，但不做谓语
一主一谓搭配好之后，多余的动词 作非谓语动词
三种非谓语动词
doing 相当于名词用，可以作主宾表
作主语
单个doing算一件事儿，所以作主语的时候算单数，后面的谓语动词要用单数；多个doing ，是多件事儿，后面的谓语动词用复数。
……suffering is inevitable……
……laughing probably has little influence on physical fitness
a little:一点儿
little :没有多少
doing sth 的 词组做成份，不是只有一个单词
（Making friends） is extremely important to teenagers……
(Broadcasting his ambition )was "very much my decision,"……
On the other hand, (putting your faith in the wrong place )often carries a high price
often 副词，修饰谓语动词carries
doing sth 的词组搭配形容词、副词、介词短语、代词变成一个很长的doing词组
doing 作主语在句首
作宾语
动宾
Americans stopped (taking prosperity for granted)
介宾
Thinking is essentially a process of( making connections in the brain)
to do相当于名词用，可以作主宾表
作主语（与同样作主语的doing 可以互换，意思上没有区别）
单个to do算一件事儿，所以作主语的时候算单数，后面的谓语动词要用单数；多个to do ，是多件事儿，后面的谓语动词用复数。
……（to decide ）is （to kill off all possibilities but one）……第一个括号是to do 作主语；第二个括号是to do 作表语
……(to anticipate every imaginable driving situation) is a difficult programming problem
doing is doing/ to do is to do (前后要对应）
To see is to believe
Seeing is believeing
眼见为实
to do sth词组
……(to anticipate every imaginable driving situation) is a difficult programming problem
在句子中的位置
句首（这种情况少）
To do so is important
so 是 代词
句尾（大多数情况下），句首用形式主语it来代替
It is important to do so
It is painful (to read these roundabout accounts today)
……it took Beaumont decades (to perfect her craft)……
It takes sb some time to do sth ：花费某人多久时间做某事
So it seems paradoxical (to talk about habits in the same context as creativity and innovation):括号里about/in/as 三个介词短语
作宾语(与dong 不可以互换）
不能接在介词后，所以不能作介宾
只能作动宾，但是不能接在所有动词后
They may then decide (to go elsewhere):may decide ：谓语动词
Fortunately ,the White House is starting (to pay attention)
it 做形式宾语
作宾语的to do 词组太长
主谓宾补的句型中
例句
The decisions made it more difficult for states to collect sales tax on certain online purchases:to do 的词组太长了 ，如果不后置，“more difficult for states”没有地方放
做表语 系动词后
The trick is to direct these funds better
The commission was also to consider possible arrangements for the War and Navy Departments
……one benefit of a "national" organization would be to negotiate better prices……with drug manufactures
done
在此不讲，因为他不能相当于名词（不能当主语宾表用）