2.I haven't eaten this kind of food before
-> this is the first time i have eaten this kind of food
3.It started raining an hour ago.
=> Is has rained for an our
4.We haven't visited my grandparents for two months.
=> The last time we visited my grandparents was 2 months ago
5.I have stuied English for three years.
=> I began studying E 3 years ago
6.My brother hasn't seen his best friend for nearly five years.
=>It's nearly 5 years since my brother saw his best friend.