Language Point 25

Natural gas, an outstanding energy fuel, can be used to heat homes, make electricity, and power cars. (Para. 12)

Meaning: Natural gas, which is an exceptional energy fuel, can be used to provide heat for homes, electricity, and even power for cars.

Notice that the phrase "an outstanding energy fuel" is an appositive（同位语）.

outstanding: a. well-known; important

Students with outstanding university records may win scholarships. 学业成绩优秀的大学生可获奖学金。

Professor Cary has a name as an outstanding lecturer. His classes are always well attended. 卡里教授上课之精彩是出了名的，他的课总是吸引着许多学生。