keep it like a warm coat because it contains like, or as, making a simile, because it says, Keep it *Like* a warm coat.
Friar Lawrence is surprised when Romeo says he loves Juliet, because he was so recently in love with Rosaline, but he agrees to marry Romeo and Juliet to potentially end the feud.
Participle, because an infinitive is the basic form of a verb, a gerund is using 'ING', so participle is the last option.
