一、two thousand 后面跟名词复数，意为“两百”
二、基数词+hundred/thousand/million/billion+可数名词复数，意为“几百/千/百万/十亿的……”
例如：Two thousand people took part in the sports meet.句意：2000人参加了运动会。
例如：Two hundred students are singing.
三、hundreds/thousands/millions/billions+of+可数名词复数，意为“数以百计的/数以千计的/成百万上千万的/数十亿的……”
例如：Thousands of trees are planted every year.成千上万的树木每年被种植。
例如：Millions of chairs are made.
