Question

correct the following sentence. thirty kilometers are a big distance​

Answer 1

Answer:thirty kilometres is a big distance

Explanation:

Answer 2

Thirty kilometers is a long distance.

Two corrections - Thirty kilometers is a long distance.

is -It is a general rule in english grammar that the singular verb is used in case of a specific quantity or amount being taken as a whole, if and when a plural noun denotes it.

Here, the 'kilometers' is plural noun which is denoting 'thirty kilometers' as a whole so instead of 'are', 'is' is used.

Long - the adjective is preferrably used for describing the length or distance. In informal or spoken English, 'Big distance' is acceptable. Big generally is used to describe size and magnitude.