ПОМОГИТЕ!! ДАЮ 25 БАЛЛОВPRESENT PERFECT/ PAST SIMPLE Изберите правильную форму:Is that

ПОМОГИТЕ!! ДАЮ 25 БАЛЛОВ
PRESENT PERFECT/ PAST SIMPLE
Изберите правильную форму:
Is that a new mobile phone?
Yes, I've just bought/ I just bought it
How much has /did it cost?
It has cost/ cost 18

Have you done/ Did you do your homework yet?
Yes, I 've finished/ I finished it last night. What about you?
No, I haven't finished/ didn't finish it yet
I have started/ I started it yesterday but I've still got a lot to do.