【请帮我修改作文的语法错误Todaywasmyfather'sbirthday.Idecidedtogivehimasurprise,soIwenttotheshopandboughtagift.Then,Iwenthomebysubwaytrain.Hadbeenthingabouthowhappyhewaswhenhereceivedthegift,Iwassoexci】

　　请帮我修改作文的语法错误

　　Todaywasmyfather'sbirthday.Idecidedtogivehimasurprise,soIwenttotheshopandboughtagift.Then,Iwenthomebysubwaytrain.Hadbeenthingabouthowhappyhewaswhenhereceivedthegift,IwassoexcitedthatIcanhardlysatonmyseatsilently.Atthenextstop,gotonagrandma,holdingtwobigbagsinherhands.Shelookedverytired.IbeganthinkingtomyselfwhetherIshouldgivemyseattoher.Thenaboutoneminutespassed,Istoodupandgavemyseattoher."Thankyou!"shesaid.WhenIheardthesewords,Ifeltveryhappy.IknowIhaddonetherightthing.Todaywasagreatday!

　　这是一篇日记