在△ABC中，cotA=$\frac{\sqrt{3}}{3}$，cosB=$\frac{\sqrt{3}}{2}$，那么∠C=____° .

不等式选讲

设函数f（x）=a（x﹣1）．

（Ⅰ）当a=1时，解不等式|f（x）|+|f（﹣x）|≥3x；

（Ⅱ）设|a|≤1，当|x|≤1时，求证： $\left|f\left(x^2\right)+x\right|\le \frac{5}{4}$ ．

函数$y=\frac{k}{x}$的图象经过点$A$$\left(1,2\right)$，则$k$的值为(    )

阅读下面这首唐诗，回答问题。

初冬夜饮               杜牧

淮阳多病偶求欢，客袖侵霜与烛盘。

砌下梨花一堆雪，明年谁此凭栏杆。

A：Hello，Xiao Hong! You look a little upset. ____

B：Yes．It's  just my mom．She always nags(唠叨)me.

A：Really? What does your mother nag at you about?

B：____"Get up now…Everything must be in place…Don't forget your piano lesson…"

A：well, all mothers like saying these words to their children.

B：Also, I'm fond of pop music.____We don't have the same interest in many things.

A：____But I should say she nags at you because she cares about you．You're lucky to have such a good mother.

B：I agree with you. ____

A：That's right. Understanding is important. If your mom knows that everything is fine,  she will never nag.