The pattern is What + noun phrase. The noun phrase can include an article, adjectives, and a noun. In speech and writing, the usual order is fixed: What comes first, then the noun phrase, then the exclamation mark. In What a mess! the noun phrase is a mess. In What beautiful flowers! the noun phrase is beautiful flowers. The structure names the thing or person and shows a strong reaction to it. For sentence order, compare this with Making Statements and Word Order.

Basic What exclamation pattern

Idea
Use What before a noun phrase to express a strong feeling about something.
Put the noun phrase right after What with normal exclamation word order.

Use What + a/an before a singular count noun. The article belongs inside the noun phrase: What a dog! What an idea! What a strange result! The noun after a/an stays singular. Without the article, the phrase is incomplete in this pattern, so What dog! does not work. The vowel sound of the next word decides between a and an. Say What a house! but What an hour!

Singular What with articles

Idea
Use What a before a singular count noun.
Do not leave out the article when the noun is singular and countable.

When the noun is plural or uncountable, leave out a/an. Use What + adjective + plural noun, or What + adjective + uncountable noun. The noun phrase can be short, as in What big shoes! or What hot weather! The adjective goes before the noun, and the exclamation mark closes the whole phrase. This pattern fits things you can count in groups, like shoes and cars, and things you cannot count one by one, like traffic or music. For punctuation in short written reactions, see Punctuation.

What exclamations with plural and uncountable nouns

Idea
Use What with a plural noun and no article.
Use What with an uncountable noun and no article.

The pattern How + adjective or adverb + subject + verb expresses a strong reaction to a quality or an action. In How kind you are!, How comes before the adjective, then the subject and verb follow. In How quickly she ran!, How comes before the adverb, then the subject and verb follow. The full clause stays in normal English order after the first word, so it follows the same sentence pattern as Making Statements, but with How at the front. In speech, this often sounds emotional, amazed, or impressed.

How exclamation pattern with qualities

Idea
Use How before an adjective to show strong feeling about a quality.
Use How before an adverb to show strong feeling about an action.

With adverbs, How is followed by the adverb first, then the subject and verb phrase. The pattern is How + adverb + subject + verb. Say How fast he drove! and How quickly they left! The adverb shows the speed, manner, or degree of the action. The verb phrase stays after the subject, so How fast drove he! is not the correct order. The same pattern works with longer verb phrases too: How carefully she was listening!

How exclamations with adverbs

Idea
Use How with an adverb when you want to praise the way an action happens.
Place the adverb before the verb phrase in the exclamation.

Use Such when the exclamation focuses on a noun phrase. The pattern is Such + adjective + noun, or Such + a/an + adjective + singular noun. Say Such a lovely day! and Such terrible luck! Use So when the exclamation focuses on an adjective or adverb by itself. The pattern is So + adjective, or So + adverb, often before be or another verb: It is so cold! She spoke so clearly! Choose Such when the noun is present and So when you want to stress the quality or manner directly.

Choosing between Such and So

Idea
Use Such before an adjective and noun phrase.
Use So before an adjective or adverb without a noun.

Short exclamations often use interjections such as Wow! Oh! Oh no! and Ah!. These words can stand alone and express surprise, pain, disappointment, or relief. Reaction imperatives also work as exclamations: Stop! Listen! Don’t do that! They use the imperative form, but in speech they often show emotion more than instruction. For the small words that begin reactions, see Interjections. For the question and statement patterns that often appear around them, see Asking Questions and Making Statements.