New Words：

sack [sæk] 麻袋；床；睡袋

Sample Sentences：

I bet he's still in the sack.
An empty sack cannot stand upright.
There was a sack of corn in the corner of the barn.
They usually have activities such as the egg and spoon race and the sack race.
Sack-race：race in which competitors put both legs in a sack and move forward by jumping

activity [æk'tiviti] n. 活动
competitor [kəm'petitə] n.竞争者；对手

标签: none