Dear Diary: Mama Please Believe me

And now a break from all the intermediate and advanced exercises I’ve been posting lately. This one is a straightforward beginner Chinese diary-style essay about a student whose mother is displeased with his (or her, it’s never clarified) homework.
Beginner Chinese Reading Materials: Learn Chinese Reading for Beginners There’s only one thing that particularly stands out to me as confusing here, which is when the mother says: 可能是有了小妹妹，我这段时间对你关心少了。 Literally, this translates as “Maybe it’s have small sister, I during this time towards you care little.” The last clause we can translate into less literal and more readable English as “I haven’t looked after you much during this time,” but the first bit, “have small sister” (有了), is confusing. Why “have” 有了?
In this case, that could be translated as, “Maybe it’s because we have your little sister,” or “It’s because I had your little sister [to look after]“, though “because” is never actually used in the sentence, it becomes that much harder to read.
Click to Listen
闷闷不乐 – mèn mèn bù lè – Sulky, moody, unhappy
怎么了 – zěn me lè – What’s wrong?
叹 – tàn – Sigh
暑假 – shǔ jià – Summer vacation
自责 – zì zé – To blame oneself
根本 – gēn běn – absolutely (not)
努力 – nǔ lì – To strive, work hard
盯 – dīng – Stare at
攥 – zuàn – To grasp
共同 – gòng tóng – Together
9月24日星期六
今天，开完家长会，妈妈闷闷不乐，我小心地问：“妈妈，您怎么了？”妈妈看着我，叹了口气说：“你暑假作业完成的不好，字也写的不好。我想，可能是有了小妹妹，我这段时间对你关心少了。”我听了，不好意思地低下了头。
看着妈妈自责的样子，我心里特别难过，我对妈妈说：“妈妈，您不要自责了，这根本就不是你的错，而是我自己不努力，请您不要生气了，从现在开始，我一定认真完成老师交给的每项作业，争取取得好成绩。请您相信我！”妈妈盯着我的眼睛，攥着我的手说：“好孩子，妈妈相信你，让我们共同努力！”
Hide English »
September 24, Saturday
Today, after my parent-teacher conference, mama looked moody, and I carefully asked her, “Mama, what’s wrong?” Looking at me, mother sighed and said: “Your summer vacation homework is not close to being done, and your writing is poor. I think, because [I've been spending so much time with] your little sister, I haven’t been paying as much attention to you during this time.” As I listened, I hung my head in embarrassment.
When I saw the self-blame on mama’s face, I was very sad, and I said to mama: “Mama, don’t blame yourself, is isn’t your fault at all, it’s that I haven’t worked hard enough, so please don’t be angry, starting now, I’ll earnestly finish all the homework teacher gave me, and I’ll fight to get good grades. Please believe me!” Mama stared into my eyes, grasped my hand and said, “Good child, mother believes you, let us work hard together.”