指学识广博而不精通to have wide but not expert knowledge

• 小王和你不一样，博而不精，认识的都是皮毛。

  Xiao Wang is different to you – he knows a lot of things, but it’s all very superficial.

• 现在是一个知识大爆炸的时代，有些外缘性的东西能做到博而不精就不错了。

  Ours is an age that has seen an explosion of knowledge. To be able to have even a superficial grasp of some peripheral topics is already commendable.