"سنفترض أنّهما زوجان."

الترجمة: We are going to assume they are husband and wife.

[FaroukZeino]

ماذا عن "we are going to assume that they are couple" ؟!

[Mary_ah]

It is correct, but you have to add an "a" before couple.

[FaroukZeino]

couple means two pairs, so its plural.

why to add an "a" ?

[Mary_ah]

couple is "a pair", which is an example itself! "a pair"

[FaroukZeino]

i mean that couple is plural word in meaning, why do we use "a" with it ?

[Mary_ah]

Couple is the same as pair/group (called collective nouns). You can say "We are going to assume they are a group/pair."

[MennaLotfy]

we are going to suppose that they are a couple