Excuse is simple, school text books.

借口很简单，学校收取教材费。

youdao

We passed our phones around to text our loved ones that we were safe and that there was a school shooter, shots were fired, and 4 students were injured thus far.

我们通过手机给我们的亲人发短信，告诉他们我们很安全，学校发生了枪击事件，到目前为止有4名学生受伤。

youdao

By 2016, the average American high school senior said they spent six hours a day writing text messages, on social media, and online during their free time.

截至2016年，美国高中高年级学生说他们在空闲时间里平均每天要花6个小时的时间写短信、上社交媒体以及上网。

youdao

(Speaking in Russian) Stelmakh says a look at school text books being published in Ukraine,the Baltics, and in other post-Soviet republics shows them to be attempts to distance those countries from Russia -- especially with regard to courses in national history.

VOA: standard.2009.12.25

Parents and guardians will be given updates about the reopening of the school via the its text messaging service and its website, a spokesman said.

BBC: Loxdale Primary School Bilston shut after metal thefts

Back in 1998, I remember marveling at high school students choosing to text one another rather than make phone calls, updating their friends with their "status" and even taking pictures with their mobile phones.

ENGADGET: This is the Modem World: Japan is not weird

It is economics 101, that every school child with an economics text book will read.

FORBES: We're All Currency Manipulators These Days