Thread: Use of на in Time Expressions

Мэри будет в Киеве неделю. OK
Мэри будет в Киеве oдну неделю. OK

It is the same. Well... almost. That is exactly the same difference as in English between "a week" and "one week."

Мэри будет в Киеве на неделю. Wrong.
Мэри будет в Киеве на oдну неделю. Wrong.

Мэри приедет в Киев на неделю. Mary will come to Kiev for a week.

The latter construction works only with verbs of motion.

Thank you very much