a. 名词从句的简化

i. That 引导的主句从句与动名词

1. That he lost the game came as a surprise to everybody
2. His losing the game came as a surprise to everybody

ii. That 引导的同位语从句与动名词

1. There was no chance that Davy would come from the battle alive.
2. There was no chance of Davy coming from the battle alive

iii. That 引导的宾语从句与动名词

1. I consider that I will emigrate to America in the future.
2. I consider emigrating to America in the future.

iv. 名词从句与不定式

1. She can’t decide whether she should go with him or stay home.
2. She can’t decide whether to go with him or (to) stay home.

b. 定语从句的简化

i. 关系词在定于从句中充当宾语，不能简化

ii. 定语从句短语

1. The girl who was standing in the corner
2. The girl in the corner

iii. 定语从句与分词

1. 分词的动作与句子谓语的动作之间的时间关系

a. The men working on the site were/are in some danger= The men who were/are on the site were/are In some danger
b. Do you know the boy who broke the window? 不能简化 为Do you know the boy breaking the window

2. 可以简化成分词短语的定语从句

a. 主从句的谓语同为现在时间
i. 主从句的谓语动词的动作都是现在的一般的的动作，即为一般时态

1. China is a developing country belonging to the third world.
   ii. 主从句的时间都表示现在，但主句的谓语表示一般状态，从句谓语表示进行的动作
2. Do you know the boy playing the violin?
   b. 主从句的谓语同为过去时间
   i. He used to live in the house facing south.
   c. 主从句的谓语时间不一致的问题

i. 不改变句子意思才能省略

1. The girl playing basketball used to be very weak.

2. 无法简化成分词短语的定语从句

a. 因时态限制不能转换
i. The girl who stood the gate yesterday is my sister
ii. Those who have finished their exercises may go now(不能用having finished 来做名词的定语)
b. 定语从句含有情态动词
i. Is there anyone who can answer the question?
c. 定语从句由be动词作谓语时
i. Those who are busy don’t have to go
d. 在一些特殊的句子里，有时由于语义上的原因，不能转换
i. The man who cooked for the students has died.
iv. 定语从句与不定式

1. 与the only, the last, the next 序数词和最高级形容词修饰的名词，后接的定语从句往往用不定式来替换
   a. You are the only one to understand me
   b. The next train to arrive is from New York.
   c. Clint was the second person to fall into this trap.

c. 状语从句的简化

i. 见第三章 省去it is，或者主谓一致时省去从句主语
ii. 状语从句与不定式

1. 目的状语从句中