如果要of的话,那就要写成：Food ran out.
run out of 是及物动词,后面要跟名词.例如：We run out of food.
the sweater就是buy的宾语,提前了.加it 就重复了.
祝你学习进步!
望采纳,谢谢!那为什么The sweater is so expensive that I can't afford to buy it.这里要加IT呵呵，这是因为这个事有一个状语从句啊，从句也好，主句也罢，一定要有主语、谓语、宾语。而前面的那句话只有一个句子啊！明白了吧，同学？再如：The shoes are too small to wear.The shoes are so small that I can't wear them.祝你好运！