下列各句中，加线的熟语使用不当的一句是（      ）

    Bob is an English boy. His eyes are blue. Li Ming is a tall boy. His eyes are black. They are good friends. Bob's hair is yellow and Li Ming's hair is black. Li Ming's mom is a Chinese teacher. Bob's mom is an English teacher.她和李明的妈妈在同一个学校。Bob's dad is a doctor(医生). Bob and his dad look different. He looks like his mom. Bob's family are new in China. Li Ming's dad and mom help them(他们). They like their English friends.

宪法是一切国家机关、社会团体和组织以及全体公民的最高行为准则。

已知双曲线$\frac{x^2}{a^2}-\frac{y^2}{b^2}=1\left(a>0,b>0\right)$的实轴长、虚轴长、焦距长成等差数列，则双曲线的离心率e为  (   )