“费力地”用英语怎么说？

查利费力地将背包背到楼上自己的公寓里。Charlie humped his rucksack up the stairs to his flat.他涨红了脸，费力地喘着气。He was going red in the face and breathing with difficulty.他费力地拄着拐杖，一瘸一拐地着向汽车走去。Using his stick heavily, he moved jerkily towards the ...