She last phoned me a month ago.
⇒ It is a month since she phoned me.
⇒ The last time she phoned me was a month ago.
⇒ She hasn't phoned me for a month.
Cấu trúc tương đương:
S + last + V(past) + O + time + ago.
= It is + time + since + S + V(past) + O.
= The last time + S + V(past) + O + was + time + ago.
= S + hasn't/haven't + V3/c3 + for + time