Thread: "На" против "Для"

За последние пять дней я спал менее десяти часов

I think I did a mistake: За последних пять дней.

iCake you have provided an excellent analysis.

And I would like to add that "На" usually is used for time periods associated with the future:
1. Я строю планы на будущее
2. Он продал свою душу дьяволу на сто лет
3. Его посадили на два года.
4. Статуя рассчитана на 40 лет
5. He will be studying for 4 years = Он будет учится на четыре года.

Originally Posted by Antonio1986

I think I did a mistake: За последних пять дней.

Um, I'm most sure I'd say за последние пять дней and not за последних пять дней. But I think both variants are possible

As for examples:

The first 4 are okay

The 5th one should be:

Он будет учится четыре года.

Because it kind of fits in this statement

Originally Posted by iCake

Нет предлога - Well, that's kind of tricky to explain this one. Well, it's usually used to say for how long the action is/was/will be active

Originally Posted by Antonio1986

I think I did a mistake: За последних пять дней.

За последние пять дней is correct. However it would be пять последних дней. The first one describes this time span as a whole, and the second one implies every of the last 5 days separately.

Originally Posted by Antonio1986

5. He will be studying for 4 years = Он будет учится на четыре года.

Он будет учиться четыре года (в течение четырех лет). Compare: Он уехал на стажировку на четыре года. I think this construction only works with perfective verbs.

Originally Posted by iCake

Он хромал десять дней - He was limping for 10 days
Я думал пять минут - I was/have been thinking for 5 minutes
Я думаю 5 минут - I am/have been thinking for 5 minutes

Only imperfective verbs here