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.

依次填入下列各句横线处的成语，最恰当的一组是（    ）

①王经理告诫年轻员工不要三心二意，，应该珍惜当前的工作机会，在平凡的岗位上做出不平凡的成绩。

②学校教育中的挫折教育很重要，如果一个人小有成就就自命不凡，，那么很可能失意时一蹶不振。

③小张出版的两本书，是在导师的指导下同学们帮着校对完稿的，他成名后竟然，对此，导师和同学们很不以为然。

实验中学初三年级进行了一次数学测验，参考人数共540人，为了了解这次数学测验成绩，下列所抽取的样本中较为合理的是（　　）。