石油 (shí yóu): petroleum

Oil is an important energy source; it can be used to produce gasoline, diesel, and plastics.

The Middle East has abundant oil resources, and many countries' economies depend on oil exports.

Because oil prices keep rising, this factory's production costs have also increased greatly.

Geologists discovered new oil reserves on the seabed and expect to begin extraction next year.

To protect the environment, many countries are reducing their use of oil and developing clean energy such as solar and wind power.