A：①②③
B：①③④
C：②③④
D：③④⑤
长期生活在沙漠中，靠行走和奔跑来寻找食物的是（ ）
— It's one of the things in the world to stay with friends.—I agree. It always makes us relaxed.
Another problem is if he can come at dawn.
NA为阿伏伽德罗常数，下列说法正确的是（ ）
