Developing new technologies are time-consuming and expensive.

Air pollution, together with littering, are causing many problems in our large, industrial cities today.

Anna Robertson Moses, who was also known as Grand Moses, is considered one of the greatest female artist of US. Art.

Practicing his speaking English everyday, his hope was to get a good job in a foreign company.

My pen has very few ink in it, so could you give me some

Conservation is the safeguarding and preservation of nature resources.

Neither of the men arresting as terrorists would reveal information about his group.

Those who had already purchased tickets were instructed to go to gate first immediately.

A smile can be observed, described, and reliably identify, it can also be elicited and manipulated under experimental conditions.

Two weeks are plenty of time to finish the assignment.

Unless there had been a heavy storm, the climbers will not have died.

Having finished his tem paper before the deadline, it was delivered to professor before the class.

Working provide people with personal satisfaction as well as money.

Mrs. Stevens, along with her cousins from Canada, are planning to attend the firework display in Da Nang, Vietnam.

Once you have finished an article and identified its main ideas, it may not be necessary to reread it again.

Although Nam worked very hard, but he didn’t pass the final exam.

In today's competitive markets, even small businesses had better to advertise on TV and radio in order to gain a share of the market.

I like the fresh air and green trees of the village which I spent my vacation last year.

The big problem was that we really did not understand what was happened

Dresses, skirts, shoes and children’s clothing are advertised at great reduced prices this week.

Although caffeine is a moderately habit-forming drug, coffee is not regarded as harmfully to the average healthy adult.