Though I wrote this sentence, I'm not sure if it is grammatically collect. `He is silly to forget to bring his lunch.' In this sentence, the author judged the man silly, for the reason that he forgot to bring a lunch with him. The former infinitive is used as an adverb phrase, and later one is as a noun phrase. Can I use them simultaneously in a sentence like this? In the same way, can I say 'You are so honest to regret having hurt him' Though the later infinitive was changed in a gerund in this sentence, I guess, if the first sentence is available, it can be too. Could you give me advise?