I go over to chat with you this evening—Nice of you! It is ____ great comfort to keep me ____company, when I’m alone at home.

When _____ help, one often says “Thank you” or “It’s kind of you”[ ]

The scientist’s many years’ careful observation ____ a surprising discovery.

My father warned me ___________ going to the West Coast because it was crowded with tourists.

Now, the world’s focus is all on Shanghai ______ the 2010 world Expo is to be held