Fortunately, the illness is fully treatable if _____ within ten days.

Nobody teaches______ English. I learn it all by______.

How do you learn English so well?—______ chatting with my uncle in America-online. [ ]

The hazy weather has ________ for almost a week in North China. —Yes, and the government has tried to solve it.

Of all the clothes stores, you can buy clothes _________in Dream Clothes.