第33讲被动语态 (by+行为者)可省略
动作的行为者不分明，或不重要或上下文中提到了行为者时，by+行为者可以省略
第34讲 被动语态，被动语态的疑问句
被动语态的一般疑问句：助动词+主语+(其它助动词)+动词过去分词……？
被动语态的特殊疑问句：
疑问词+助动词+主语+(其他助动词动词)+动词过去分词~？
第35讲非谓语动词 to+动词原形 VS 动词原形+ing
1.动词不定式，由to+动词原形构成，可以做主语,宾语,宾补,定语 表语和状语.
主语:
To get there by bike will take us an hour.
宾语:
The driver failed to see the car in time
宾补:
We believe him to be guilty
定语：
The next train to arrive is from Beijing.
表语和状语：
My suggestion is to put off the meeting.
I come here only to say goodbye to you.
2.动词原形+ing可作动名词用，具有动词的特征和变化形式，但在句子中的用法及功能类同名词:在句子中可以做主语，宾语，表语，定语，它也可以被副词修饰或者支配宾语
Reading is an art.
They went on working and never stopped talking.
Your task is quickly cleaning the room.
This is a reading room.
来源：oschina
链接：https://my.oschina.net/u/4454049/blog/3213016