Nouns used only in the plural
Some English nouns are usually used only in the plural. Such nouns take a plural verb, and generally have a plural form. For instance, the following nouns, which all refer to objects with two parts, are usually used only in the plural:
If it is desired to refer to such objects individually, the expression pair of is often used.
e.g. a pair of jeans
a pair of pajamas
a pair of pliers
a pair of scissors
When the expression pair of is used as the subject of the verb, the verb must agree with the word pair.
e.g. Jeans are fashionable.
A pair of jeans is expensive.
Pliers are very useful.
A pair of pliers is often useful.
In the above examples, the nouns jeans and pliers take the plural verb are, and the noun pair takes the singular verb is.
التوقيع لقوي ثامر