It是形式主语。真主语是to heat…,当然也是to cost...的逻辑主语,这不矛盾。比如He wanted to leave soon. He既谓语动词wanted的主语,同时也是不定式to leave...的(逻辑)主语。heating oil中的heating是动名词,表示oil的用途,就像reading room表示room的用途一样。
It's projected to cost more than $2,300 to heat a typical home with heating oil this winter.
1.to heat…感觉是cost的逻辑主语,但这样不就少了it作为形式主语吗?
2.heating oil中heating是动名词还是现在分词