Around 150 B.C. the Greek astronomer Hipparchus developed a system to classify stars according to brightness.

Now I understand why you moved out of that house.

No vehicle weighing over 3.5 tons is allowed on this bridge, according to traffic signs placed at both ends of the structure.

He resembles his brother in appearance very much, which makes his friends unable to recognize.

I didn’t think his the comments were very appropriate at the time.

The yearly growth of the gross national product is often used as an indicator of a nation's economy.

Professor Berg was very interested in the diversity of cultures all over the world.

S. Mayo Hospital in New Orleans was so named in recognition of Dr. Mayo’s outstanding humanitarianism.

Once in a while I visit my grandparents on the farm and stay there for some days.

All classifications of human societies and cultures are arbitrary.

I told you clearly and definitely not to write your answers in pencil, Smith!

A brief outlined of the course and bibliography were handed out to the students at the first meeting.

He made one last futile effort to convince her and left home.

In the 1776 pamphlet "Common Sense," Thomas Paine defended the cause of the American Revolution.

If petrol price go up any more, I shall have to use a bicycle.

The ages of the two children put together was equivalent to that of their father.

I didn’t think his the comments were very appropriate at the time.

Most of the school-leavers are sanguine about the idea of going to work and earning money.

These were the people who advocated using force to stop school violence.

The use of lasers in surgery has become relatively commonplace in recent years.

Sorry, I can’t come to your party. I am snowed under with work at the moment.