11. 误：Why to stay here so long ?

　　 正：Why stay here so long ?

　　 析：why + 不带 to 的动词不定式构成的问句表示"责备"或"不同意"。

10. 误：Making a plan first is a good idea .

　　 正：To make a plan first is a good idea .

　　 析：动名词表示经常性，习惯性的动作；而不定式表示具体的一次性动作。

9. 误：- I’d like to buy an expensive sports car .

　　　 - Well , Mike , we‘ve got several models to choose from .

　 正：-I’d like to buy an expensive sports car .

　　　　　 -Well , Mike , we‘ve got several models to choose .

　 析：不定式短语作后置定语，并且与其所修饰的词构成逻辑上的动宾关系，不定式短语中的动词必须是及物动词或相当于及物动词的短语。但此处 choose 本身是及物动词，故不需 from。

8. 误：As I got to Paris , she was beginning studying French in a language school .

　 正：As I got to Paris , she was beginning to study French in a language school .

　 析：begin 和 start 之后既可以接不定式作宾语，也可以接动名词作宾语，但以下三种情况只能接不定式作宾语 . 1 ) 物作主语；2 ) 本身是进行时态；3 ) 其后接的是表示心理变化的动词。

7. 误：Oh , it’s very cold here , let‘s make a fire warm ourselves up .

　 正：Oh , it’s very cold here , let‘s make a fire to warm ourselves up .

　 析：此处不定式短语作目的状语，相当于 in order to do或so as to do。

6. 误：Tom ought not to tell me your secret , but he meant no harm .

　 正：Tom ought not to have told me your secret , but he meant no harm .

　 析：ought to / should + have done sth . 表示本来应该做某事，而实际未做；ought not to / shouldn‘t + have done sth . 表示本来不应该做某事，而实际做了。

5. 误：Rather than to ride on a crowded bus , he always prefers riding a bicycle .

　 正：Rather than ride on a crowded bus , he always prefers to ride a bicycle .

　 析：prefer 的用法如下：

　　 prefer to do A rather than do B

　　 prefer doing A to doing B

4. 误：The boy wanted to ride his bicycle in the street , but his mother told him not to do .

　 正：The boy wanted to ride his bicycle in the street , but his mother told him not to .

　 析：在不定式作宾补或含有不定式的简单答语中，为避免重复，可省去其后的动词原形，但动词不定式符号不可省，又如 would like to , used to , be going to 等。

3. 误：Paul doesn‘t have to be made learn . He always works hard .

　 正：Paul doesn’t have to be made to learn . He all ways works hard .

　 析：动词 feel , listen to , hear , have , make , let , see , watch , notice , look at , observe , 接不定式作宾补应省略 to，但在被动语态中应加上。

2. 误：We agreed to have met here but so far she hasn‘t turned up yet .

　 正：We agreed to meet here but so far she hasn’t turned up yet .

　 析：不定式的完成式表示动作已发生，由句意看出"她还未露面"，所以应该用一般式。