Когда пишется is когда are когда a когда an? когда it когда it s 22 .

He, she, it - is
you, we, they -are
an apple
a pineapple
когда с гласной, то аn, конда с согл., то а

Is --> he, she, it (единственное число)

are --> we, they, you (множество)

пример №1:

There is a computer on the table.

There are much money on the table.

пример 

She is a student.

They are students.