1st of all, "trace back" is a phase.
If use it as a verb, "I trace" is formal, but there is something called "omitted subject pronouns"
example:
我決定今晚飛起老婆同羅莎蓮撐枱腳,於是call佢:
Hey honey, i'm afraid we have to take a rain check for tonight’s anniversary dinner.
Oh no, again? 我聽出佢把聲想喊,但望住身邊的羅莎蓮,我把心一橫:I’m sorry, something comes up at work. but I promise you I'll make this up when I can. ok?
ok, you take care, love you.
Love you too.
然後我啜一聲錫咗身邊的羅莎蓮一啖,老婆聽到,仲以為我電話傳吻。一啖可以錫兩個女人。
"love you" 就得咖啦, "I "可以omit.
Don't know where God is but the Devil is in the details