เธอมีเพื่อนต่างชาติคนหนึ่งเขากับเธอ

She has a different one: he and she knew for about three months earlier
but suddenly he was gone (to be sure)
then he came back again with a letter (usually they talk via email. )


I do not know what to do.To answer letters or stop.

She is one of the foreign friends
he is about 3 months with her previously known
but all of a sudden they disappeared (probably next exams)
then he came back again with a letter (usually, they talk to each other via e-mail)

, she does not know what should be done?
.To respond to the letter or to stop.

She has a friend with him
foreign one of her known for about 3 months earlier, but suddenly he disappeared
(exams should be attached)
and then he came back again and again with a letter (usually they were talking, the e-mail)

she didn't know what to do
To answer a letter, or will stop