My student is confused about these two sentences.
Well-known journalist Kent Moriwaki published a book in May (featuring) a compilation of quotes.
They have proposed a drainage system (designed) to keep the highway dry during heavy rain.
He doesn't understand why we have to use "~ing" in one sentence and "~ed" in the other. Is there a way to simply explain this?
The gerund-participle clause featuring a compilation ... means the same as the relative clause which features a compilation ... but is more economical.
The book features, it is active voice, and hence we use the gerund-participle.
Designed to keep ... means the same as the relative clause which is designed to keep ... The relative pronoun and the BE are omitted for economy.
The drainage system is designed, it is passive voice, and hence we use the past participle. It would be hard to construct using the gerund-participle designing.
Possible long forms of the two original sentences are
... Kent Moriwaki published a book in May which features a compilation of quotes.
They have proposed a drainage system which is designed to keep the highway dry ...
