Looking at the three news sites I cannot find anything that is covered by all three of them, but I did find a story covered by Al-Jazeera and The Guardian.
It is about the Dhaka fire/Dhaka skyscraper. A fire broke out in a skyscraper in Bangladesh, at least 5 people have been confirmed dead and many others are treated at hospitals. People are still trapped inside the building and many have jumped from the skyscraper hoping to survive.
The Guardian seem to focus on political issues and worldwide happenings, such as punishing gay sex by stoning, racism and scenarios about robots and other tech. They also seem very interested in the ongoing Brexit deal as of right now.
Los Angeles Times focuses a lot on ´less important news´, such as “Are Arabs and Iranians White?” and a policeman getting fired for going into a strangers house. But their first and most noticeable post is about Trump ending the HIV epidemic but San Francisco could get there first. Which is more important, however still a bit weak.
Al-Jazeera prefers the big news. Like the Dhaka fire, Trump telling Russia to get its troops out of Venezuela and Bosnians deported from Croatia for refusing to spy on Muslims. In my opinion Al-Jazeera has the most interesting news, they also focus a bit on Trump who is a very interesting person.
The Guardian on Facebook covers the exact same as in their home site. They still really enjoy the Brexit deal and seem to mostly cover the same issues over again.
Al-Jazeera on Facebook however posts about different topics than their home site. Here they focus more on gun massacres, the desert rose museum and people defending their land. They probably post different things on Facebook, because they do not want to feed their readers with the same information. They know the people who follow them on Facebook checks their home site as well.
CNN on Facebook focuses on different things just like Al-Jazeera, but even though the information is different they still write about the same people. CNN definitely likes political issues, and especially on their Facebook page they post a lot on president Trump. I feel CNN knows their audience, they know what the readers want. They do not post the same, instead they ´abuse´ the same source again to give out as much information as they can.