例句:The Middle East is the world's single most important source of oil.
中东是世界上最为重要的一个产油地。
2.as well as 和...一样；也
例句:Moral as well as financial support was what the West should provide.
西方国家应该提供道义支持和经济援助。
3.natural gas 天然气
例句:Today, oil and natural gas have replaced coal and wood in most areas.
如今在大部分地区，燃油和天然气已经取代了煤炭和木头。
4.so long as 只要
例句:The president need not step down so long as the elections are held under international supervision.
只要选举在国际监督下进行，总统就不用下台。
