内容: 1.catch up with意为“跟上;赶上”。如: If you study hard ,you ’ ll catch up with other students.如果你努力学习的话,你将会赶上其他同学。 2.cheer up意为“使……振奋;使……高兴起来”。如: He sings for many people at the city hospital to cheer them up.他在城市医院里为很多人唱歌,使他们振作起来。 3.clean up意为“清除;收拾干净”。如: We should not litter the seas ,a...