Question

英语疑难问题

If we remain inveterate smokers, it is only because we have so often experienced the frustration that results from failure.
1。不太了解it is only because在这里的用法，it is only because后是不是省略了that，
2.。不太了解that results from failure的意思。

Answer 1

本来 because后就无that，
that results from failure定语从句，导致失败