as a young man, he saw the great need for increasing the rice output.(答案是increasing做宾语)Yuan Longping searched for a way to increas rice harvests without expanding the area of the fields.(答案是expanding 做状语)请解释这两题答案的理由,并分析介词后面的现在分词是宾语还是状语,区别的标准。谢谢