by all means （表示许可）好的，当然可以。
= used to give permission 补充by no means决不，一点都不
=not at all。这两个词组都是by...means的形式，词义需要注意下。

【例句】
"May I borrow this book?" "By all means."
“我可以借这本书吗？”“当然可以。”

It is by no means certain that we'll finish the project by June.
我们能否在6月份前完成这项工程还很不确定。