too…to的用法语法

"Too...to"结构表示“太...而不能”，用于表达某事因为某种原因而无法实现。例如："He is too tired to go out."（他太累了，不能出去。）语法要点：1. "too"后面跟形容词或副词。2. "to"后面跟动词原形。3. 表示否定意义，相当于"not...enough to"。注意："too"和"so"都可以表示否定，但用法不同。"too"用于否定，"so"用于强调。例如："He is too tired to go out."（否定）和"He is so tired that he can't go out."（强调）。

The 'too...to' structure is a common English grammatical pattern used to express the idea that something is more than necessary or desirable, or beyond a certain degree, making it impossible or unlikely for an action to occur. This structure is formed by placing an adjective or adverb before 'too', followed by 'to' and then the base form of a verb, typically translating to "so...that one cannot...".

Basic Usage of 'too...to'

Here are some examples to illustrate the basic use of 'too...to':

• He is too shy to give a speech, indicating his shyness prevents him from speaking.
• It's too far to get there on time, suggesting the distance makes punctuality impossible.

Introducing the Logical Subject with 'for'

Sometimes, the infinitive following 'too...to' can be preceded by a logical subject introduced by the preposition 'for':

• It's too expensive for her to buy, meaning the cost is beyond her purchasing power.
• The box is too heavy for the boy to carry, indicating the weight is more than the boy can handle.

Determining Whether the Infinitive Takes an Object

The presence of an object in the 'too...to' structure depends on whether the verb is transitive:

• He is too tired to go any further, suggesting exhaustion stops him from proceeding.
• The room is too dirty to live in, indicating the state of the room makes it uninhabitable.

Use of Passive Voice in Infinitives

The infinitive in 'too...to' structures can also be in the passive voice:

• The text is too difficult to understand, meaning it's hard to grasp.
• The text is too difficult for the students to understand, showing it's beyond the students' comprehension.

Conversion to 'so [such]...that' Structure

The 'too...to' structure can be converted to the 'so [such]...that' structure for alternative expression:

• The child is too young to dress himself becomes The child is not old enough to dress himself.
• The box is too heavy for me to carry becomes The box is so heavy that I can’t carry it.

Positive Meanings with 'too...to'

Interestingly, 'too...to' can sometimes convey a positive meaning:

• He is too clever not to understand this, suggesting his intelligence ensures understanding.
• Never too old to learn, which is an encouragement to continue learning regardless of age.

Understanding the 'too...to' structure enriches one's ability to express limitations and impossibilities in English, offering a nuanced way to communicate the extent to which certain conditions prevent actions.