He ran quickly to catch the departing train.
Meaning: This sentence means that he moved rapidly in order to get on the train before it left.
Choice of Words: Quickly is an adverb that describes the manner in which something is done. Catch is a verb that means to seize or capture something. Departing is an adjective that describes something that is leaving or going away. When you put them together, "He ran quickly to catch the departing train" means that he moved rapidly in order to seize or capture the train that was leaving.
Alternative Expressions
Related Expressions