It is an undeniable truth that a coherant grasp of the nature of first
language learning is an invaluable aid, if not an essential component, for
a better understanding of second language acquisition. However, the ideas
generated from L1 acquisition are often misapplied in foreign language
teaching/learning. Provide three examples to illustrate how they are
misapplied.
请问句话是什么意思? 这里的 the ideas 指的又是什么?

大致上的意思是,母语的掌握程度对学习外语很有用,但一些源自于母语的概念会误导外语的教学上,请举出三个例子说明这些概念是怎么误导教学的