`1.` It is ten days since I last saw Mo.

`→` The last time I saw Mo was ten days ago.

`→` I haven't seen Mo for ten days.

`2.` 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.

`3.` 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.

`4.` It is eight months since it last rained.

`→` The last time it rained was eight months ago.

`→`  It hasn't rained for eight months.

`5.` It is six weeks since it last snowed.

`→` The last time it snowed was six weeks ago.

`→`  It hasn't snowed for six weeks.

`6.` It is an hour since Tom last cried.

`→` Tom last cried an hours ago.

`→` Tom hasn't cried for an hour.

`7.` It is three years since I last saw you.

`→` The last time I saw you was three years ago.

`→` I last saw you three years ago.

`8.` It is a month since I last watched TV.

* Giải thích các bước làm :

S + last + V quá khứ + thời gian ( 2 days ago/in 2010)

= The last time + S + V quá khứ + was thời gian 

= S + have/has not + VPII + for/since thời gian

= It is + Thời gian + since + S + last + V quá khứ