Don't be afraid to ask questions. Don't be afraid to ask for help when you need it. I do that every day. Asking for help isn't a sign of weakness, it's a sign of strength. It shows you have the courage to admit when you don't know something, and to learn something new.

Part of people's concern is just the sense that around the world the old order isn't holding and we're not quite yet to where we need to be in terms of a new order that's based on a different set of principles, that's based on a sense of common humanity, that's based on economies that work for all people.

More people are realising that ISIL's not a caliphate. It's a crime ring.

For we have a choice in this country. We can accept a politics that breeds division, and conflict, and cynicism. We can tackle race only as spectacle - as we did in the OJ trial - or in the wake of tragedy, as we did in the aftermath of Katrina - or as fodder for the nightly news. We can play Reverend Wright's sermons on every channel, every day and talk about them from now until the election, and make the only question in this campaign whether or not the American people think that I somehow believe or sympathize with his most offensive words.

I've said to [Donald Trump], and I think others have said to him that the day that he is the President of the United States, there are world capitals and financial markets and people all around the world who take really seriously what he says, and in a way that's just not true before you're actually sworn in as president.

I want every math teacher to know math. I want every science teacher to have expertise in science. I want them to know how to inspire and engage young people.

We've got to identify new strategies to use cleaner energy, because that is a recipe for reducing the overall amount of pollution that's out there.