$\color{black}{1}$

→  We have eaten dinner for 20 minutes.

$\color{black}{2}$

→ My father has designed shirts since 2009 .

$\color{black}{3}$

→ I have worked here For four months .

$\color{black}{4}$

→ She has written novels since last year.

$\color{black}{5}$

→ They have hunted animals for two hours .

$\color{black}{6}$

→ They have collected water since last week

$\color{black}{7}$

→ She has herded buffaloes since june

$\color{black}{8}$

→ I haven't smoked  to her two years ago

$\color{black}{9}$

→ Nam hasn't met his aunt since December

$\color{black}{10}$

→ I haven't worn those jeans in 2011

$\color{black}{11}$

→ She hasn't seen for 2 hours .

$\color{black}{12}$

→ She hasn't met her brother since Wedding

$\color{black}{-}$ $\color{black}{-}$ $\color{black}{-}$ $\color{black}{-}$ $\color{black}{-}$

S + Started / Began + V/Ving + ......ago/in + ( 2009 )

→ S + Have/Has + V3/Ved +.....since/for 

S + Last + V2/Ved  + in/ when +.....ago

S + Haven't/Hasn't + V3/Ved + since+.....for

It is + time + since + S + ( Last ) + Ved/V2 +...

The last time +  S + V2/Ved + Was + ( month ) + ago

                                                 Was +in ... (2010 )