The qualifying infinitive

The qualifying infinitive may be used:
1) to qualify a noun like an adjective

• Give me something to drink.
• Give me a chair to sit.
• It was a sight to see.
• This is a thing to admire.

2) to qualify a verb like an adverb

• I came to see you.
• We are going to play the match.
• It is going to rain.

3) to qualify an adjective like an adverb

• The book is nice to read.
• This picture is beautiful to look at.

4) to qualify a sentence

• To tell the truth, you are a fool.
• To be frank, I don’t like him.

When the infinitive is used to qualify a noun, verb or adjective, it is called a qualifying infinitive or gerundial infinitive.
Adjectives / adverbs and the qualifying infinitives are compared below.

• That was a beautiful sight. (Here the adjective beautiful qualifies the noun sight.)
• That was a sight to see. (Here the infinitive to see qualifies the noun sight.)
• He came quickly. (Here the adverb quickly modifies the verb came.)
• He came to see us. (Here the infinitive to see modifies the verb came.)
• This kind of tea is very good. (Here the adverb very modifies the adjective good.)
• This kind of tea is good to drink. (Here the infinitive to drink modifies the adjective good.)

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