They worked very hard in spite of their old age.17/20They worked very hard in spite of their old age.Despite they were old, they worked very hard.Although they were old, they worked very hard.Though they were old age, they worked very hard.Even though they old, they worked very hard.Giải thíchĐáp án đúng: B Dịch: Mặc dù họ có tuổi, họ làm việc rất chăm chỉ.