1. She last phoned me a month ago.

 -It is a month since she last phoned me.

 -The last time she phoned me was a month ago.

 -She hasn't phoned me for a month.

2. They last ate fish a year ago

- It is a year since they last ate fish.

 -The last time they ate fish was a year ago.

 -They haven't eaten fish for a year.

`1.` It's a month since she last phoned me. 

`=>` The last time she phoned me was a month ago.

`=>` She hasn't phoned me for a month.

`2.` It's a year since they last ate fish.

`=>` The last time they ate fish was a year ago.

`=>` They haven't eaten fish for a year. 

`________________________`

`@` Cấu trúc:

`-` S + last + V2/ed + khoảng thời gian + ago. : Lần cuối cùng ai làm gì đã bao lâu ... 

`=` It's + time + since + S (last) + V2/ed : Đã bao lâu kể từ khi ai đó (lần cuối cùng) làm gì ...

`=` The last time + S + V2/ed + was + time : Lần cuối cùng ai làm gì đã bao lâu ...

`=` S + have/has not + V3/ed + since/ for + mốc tgian/ khoảng tgian : Ai đó đã không làm gì kể từ khi ...