We must keep on learning if we want to keep up with the     of the changing times.

 His name is on the _______ of my tongue, but I just couldn’t remember it.

I’m looking for an opportunity to display my _____ in advertising.

The most important _____ of his speech at the G20 summit was that we should all unite to fight against the financial．

I paid him ￡50 for the painting, but its true ______ must be at least ￡500.