The government has taken measures         air quality.

From the dates        on the gold coin, we know that it was made 500 years ago.

The Diaoyu Islands have been part of China’s territory since ancient times, __________ as important fishing grounds of Taiwan.

After completing and signing it, please return the form to us in the envelope ________.

Driving along the Congtai Road in the rush hour, you will surely get _______ in the traffic jam.

The bridges over the Fuyang River have been rebuilt, _________ it possible for boats to sail.

Please tell me the problems ________ at yesterday’s meeting quickly. The manager is calling me!

______himself to his research on the IT technology, he soon made a breakthrough.

----What’s it that cost him the job?
----_______ experience .He was always very nervous.