____ wide spread of H1N1 is _____ challenge for the whole world. Confidence, cooperation and responsibility are keys to overcoming it.
A clean environment can help the city bid for the Olympics, which ______ will promote its economic development.
It’s quite _____ of beginners to forget to use an article before a noun.
Qingdao is _____ most beautiful coastal city and I think I’ll go there for _____ second time.
—How do you find your new pen? —Wow, _____. It’s really worth the money I paid.
It’s dangerous if you have the fire _____ all night long.