费力

laborious; strenuous; effortful; arduous; toilsome; hard; taxing; demanding; exert; strive; toil; put effort into; work hard at; strain; arduously; laboriously; strenuously; effort; exertion

前进

advance; move; move forward; proceed; press on; forge ahead; march; progress; push forward; gain ground; make headway; go forward; go ahead; make progress; make one's way; forward; progressive; onward; onwards; ahead; ascent; advancing; progression; forward movement; onward march