it is always a good idea to do some homework before you give a (speak)

Firstly, "always" is a dangerous word all the way. Nothing can be described as "always" as far as I am concerned. But to do some praparation is a must. For instance, if you wanna give a speak or a presentation in public, you`d better settle a suitable topic, and the related material. In this way to make sure that the details in your speech are all correct, what`s more you could search for some interesting stories for your topic, thus could gain more attention from listeners and audiences.

Itis always a good idea to do some homework before you give a speech。此处用名词。意为：在作发言之前作一些准备总是一个好主意。

it is always a good idea to do some homework before you give a (speech)

speech 名词，speak的名词 演讲