The only evidence was cut into a tree and a fence: the letters C-R-O and the word Croatoan,C-R-O-A-T-O-A-N.

VOA: special.2009.08.17

And the last example that we're going to talk about is thionyl chloride, so it's s o c l 2. This is another good step forward, because now we actually have four different atoms in our molecule.

我们要讨论的最后一个例子,是氯化亚砜，就是硫，氧，氯，二，这又是一个进步，因为我们的分子中现在有四个不同的原子了。

麻省理工公开课 - 化学原理课程节选

"By two thousand and twenty, C.O.P.D.will likely be the third leading cause of death across the world."

VOA: special.2009.06.23

The team examined results from a Norwegian study of more than nine hundred people with C.O.P.D.

VOA: special.2009.06.23

The team examined results from a Norwegian study of nine hundred fifty-four people with C.O.P.D.

VOA: special.2009.06.03

Doctor Soerheim says they show that women suffered the same severity of C.O.P.D.as men.

VOA: special.2009.06.03

The United Nations agency UNESCO created the Intergovernmental Oceanic Commission, or I.O.C.,in nineteen sixty.

VOA: special.2009.03.17

She says they show that women suffered the same severity of C.O.P.D.as men.

VOA: special.2009.06.23

The I.O.C.says its efforts are the beginning of a worldwide tsunami-warning program.

VOA: special.2009.03.17

The United States is one of thirty-one countries in the O.E.C.D Gaetan Lafortune says in recent years many of the countries increased their efforts to hire foreign nurses.

VOA: special.2010.06.07

It was a short way of writing a different spelling of the words all correct. Some foreign-born people wrote all correct as o-l-l k-o-r-r-e-c-t, and used the letters O.K.

VOA: special.2010.02.28

C.O.P.D.,chronic obstructive pulmonary disease, blocks airflow through the lungs.

VOA: special.2009.06.03

In the Washington area, the C&O Canal still holds water.

VOA: standard.2010.04.29

Mule stables dotted the route. But the canal company ran out of money as faster railroads stole most of their business, and the C&O Canal never reached Pittsburgh and the Ohio River.

VOA: standard.2010.04.29