Unit 4 Global warming
5. it is the greenhouse effect that gives the earth’s surface the average temperature of 15℃
溫室效應(yīng)使得地球表面的平均氣溫達(dá)到了15℃.
6. together, individuals make a difference. 眾人拾柴火焰高。
7. your contribution counts. 你的貢獻(xiàn)很有價(jià)值。