I work as a volunteer for an organization that helps the poor in Haiti. Recently I took my son Barrett there for a week, hoping to   1 him.
        Before setting out, I told Barrett this trip would be tiring and   2 . For the first two days, he said almost nothing. I worried the trip was too 3 for a 17-year-old. Then, on the third day, as we were 4 over high rocky mountains, he turned to me and grinned(咧嘴笑), “Pretty hard. ”