never did I have doubts if I could do it.

这句话什么意思，求语法剖析。

看不明白。不懂什么使用方法呢。

网友了解英语的倒装句吗？语法书有专门论述。这句话等于：
Never did I have doubts if I could do it.
I never had doubts whether I could do it.

【直译】我从来没过我能否做那件事的怀疑。
【翻译】我从不怀疑我是不是能做到。

目前懂了吗？