Before the problem can be solved，it must be obvious ________ the problem itself is.(2011·湖南，31)

________ to see us, the professor gave us a warm welcome.

Tmall.com is booming, especially during the festivals，______________ price and variety, it is superior to other online shopping sites, like amazon.com and 360buy.com

Drink some hot milk _____ you will feel better.

The living room is clean and tidy, with a dining table already ________ for a meal to be cooked [ ]