单选题
Scientists will have to______new methods of increasing the world's food supply in order to solve the problem of famine in some places.
【正确答案】
D
【答案解析】解析：come up for air喘口气，调节一下精神；come down with付钱，染上(病)；come down to屈尊做某事，归结起来(为……)；come up with追赶上，想出，提出。提出想法／建议come up with a plan／method．