一、当主句谓语动词是 decide，hope， wish， choose， agree， promise 等，且宾语从句的主语与 主句的主语一致时，宾语从句可简化为不定式结构。例如：
(1) Tom hopes he will go to his hometown in two days.
→ Tom hopes to go to his hometown in two days.
汤姆希望两天后去他的家乡。
(2) We decided that we would help him finish the work on time.
→ We decided to help him finish the work on time.
我们决定帮他按时完成这项工作。
二、当主句的谓语动词是order（命令），require （需要）等时，如果主句和从句的主语不一致，宾语 从句可简化为“名词（代词）+不定式”结构。例如：
The boss ordered that we should start at once.
→ The boss ordered us to start at once.
老板命令我们马上开始。
三、当主句谓语动词是know， learn， remember， forget， tell 等动词，且主句主语与从句主语一 致时，宾语从句可简化为“疑问词+不定式”结构。例如：
(1) She has forgotten how she can open the window.
→ She has forgotten how to open the window.
她已经忘了怎样打开窗。
(2)Kate didn’ t know what she should do .
→ Kate didn’t know what to do.
凯特不知道做什么。
注：当主句谓语动词是tell， ask， show， teach 等动词，且后带双宾语，从句主语和间接宾语一致时， 宾语从句可简化为“疑问词+不定式”结构。例如：
Could you tell me how I can get to the station？
→ Could you tell me how to get to the station？
你能告诉我怎样到达车站吗？
四、某些动词后的宾语从句，可以用介词加动名词（短语）等其他形式简化。例如：
（1）The poor boy doesn’t know when and where he was born.
→The poor boy doesn’t know the time and the place of his birth.
可怜的男孩不知道他的出生时间和地点。
（2）I don’t understand what you said.
→I don’t understand your words. 我不明白你所说的话。
（3）Can you tell me how I can get to the hospital?
→Can you tell me the way to the station? 你能告诉我去医院的路吗？
五、某些动词后面的宾语从句可转化为“宾语+ V-ing 形式（作宾语补足语）”结构。例如： The girl found that there was a book lying on the desk.
→ The girl found a book lying on the desk.
女孩发现桌子上有一本书。
六、动词seem后的宾语从句，也可以用不定式（短语）来简化，但句型需要进行适当的变化。例如：
It seemed that she was afraid of the dog.
→She seemed to be afraid of the dog.
除上述方法外，还有一些特殊句式的转化。例如：
(1) I found that it was easy to solve the problem.
→I found it easy to solve the problem.
我发现解出这道题很容易。
(2) Soon the boys found that the ground was covered with thick snow.
→ Soon we found the ground covered with thick snow.
不久这些男孩发现地面上覆盖了厚厚一层雪。
(3) My friends found that the table was very beautiful.
→ My friends found the table very beautiful.
Exercises: 将下列句子改为简单句
1. He wants to know when he will plant trees in the park.
He wants to know _________.
2. Rose doesn't know how she can cook delicious beef noodles.
Rose doesn’t know________.
3. The students wonder what they should do next.
The students wonder __________.
4. I didn't know whether I would buy a bike or not.
I didn’t know ___________.
5. Could you tell me where I will go.
Could you tell me _________.
答案：
1. when to plant trees in the park.
2. how to cook delicious beef noodles.
3. what to do next.
4. whether to buy a bike or not.
5. where to go
Let's learn Object Clause.