Question

one of those boys______ a long knife (have/has) ​

Answer 1

Answer:

has

Explanation:

One of those boys has a long knife.

In the sentence we use has as the sentence says that one of the the boys has the knife not all of them.

Hope that helps you...☺

Answer 2

Answer:

has is the answer

Explanation:

one of the boys has a long knife

as here the sentence explains about present continuous ,and have is being is used in past form

So, has is the correct option