To express admiration or/and surprise in English we can use How and What (a/an). But how do we use them?

How is followed by an adjective or an adverb

How smart he is! , How lazy you are!
How carefully she drives!

What is followed by adjective+ noun.

If the noun is uncountable or a plural noun we use:
What +(adjective) + noun:

What good weather! (not what a good weather)
What beautiful earrings! (not what a colourful earrings)

If the noun is a singular countable noun we use:
What + a + (adjective) + noun:

What a terrible mistake it was to tell her the secret.
What a funny joke!

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