protest against something
protest about something

People had been protesting about something - but then, they always were.

First of all, children were likely to protest about their parents' departure.

Were you protesting about the lack of spending in 2008?

Children may protest about family activities, but then, that's tradition, too.

The workers protest about shortages in the supply of food.

China has also protested frequently about the size of its trade deficit with Japan.

And the police have protested most strongly about your interference.

The activity has not been without controversy however and local people near the site have sometimes protested about certain aspects of the development.

To my knowledge, she never whined or protested about her life with him.

Monumental is the word, and I must gently protest about its size.

This, I think, is what some people mean when they say that many of the protesters don't know what they're protesting about.

Hundreds of protesters arrested in Russia, but what were they protesting about?

But there are, with all due respect, much more important things we should be protesting about.

I mean, now that I've got a real animal to protest about.

So even a modest slowing of China's growth rate would mean more economic frustration for people to protest about.

After a while, a young guy sitting in the corner nearest us finally asked what we'd been protesting about.

It gave his tense stomach something real to protest about.

Yeah, he may be hotter, but is it really worth protesting about?

Where was all this massive deforestation the environmentalists were always protesting about?

You guys don't have anything to protest about, do you?