During the flood many students volunteered through the weekend, giving out food and water for the victims.
A. working
B. to work
C. to have worked
D. having worked
网友回答
A. working
(答案→)B. to work
C. to have worked
D. having worked
解析：B考察非谓语动词，句义：在洪水期间，很多学生自愿利用周末的时间为灾民发放食物和水。Volunteer to do sth自愿做某事。符合语境。故B正确。