This is because let is a globally-defined identifier.

这是因为let是一个全局定义的标识符。

youdao

I let him tag along because he had not been too well recently.

我让他跟着走，因为他最近一直感到不太舒服。

《柯林斯英汉双解大词典》

I had to let them into the building because they had lost their keys.

我不得不允许他们进楼，因为他们丢了钥匙。

《柯林斯英汉双解大词典》

Treasury Secretary Tim Geithner says the financial crisis developed in part because the existing system let some companies "shop for the weakest regulator."

VOA: special.2009.06.19

So hopefully, it was a time issue in terms of looking at the periodic table, because let's have you tell me what are we looking for here?

希望刚才大家出问题的原因,是因为看周期表有时间限制，请大家告诉我,我们在这里找什么？

麻省理工公开课 - 化学原理课程节选

because I said, "Listen, I got a great idea, let's go for it." And she did exactly what I said.

因为我说：“听着，我有个好主意，我们研究吧。”我怎么说她就怎么做。

中国学生的特点 - SpeakingMax英语口语达人

Because let me just say this -- in a tight race, it is the ground game that makes the difference.

WHITEHOUSE: Remarks by the First Lady at a Campaign Event -- La Jolla, CA

Sure -- not that it matters, because let's be honest, there isn't a chance in hell that's going to be happening any time soon.

ENGADGET: Motorola's cellphone business needs a new leader: okay, I'm in.

And I think that baseball has compromised its record book by allowing these players to use these drugs, because let's face it, baseball has been thrilling.

NPR: Baseball, Steroids and Barry Bonds