the last time I studied English was 3 days ago

`-` It's 3 days since I last studied English.

`-` I last studied English 3 days ago.

`-` I haven't studied English for 3 days.

`××××××××××××`

`+` The last time + S + Ved + was + thời gian + ago.

`=` It + is/has been + thời gian + since + S + last + Ved

`=` S + last + Ved + thời gian + ago

`=` S + hasn't/haven't + P2 + since/for....