Identify the function of the gerund in this line from Shakespeare's 'Hamlet': 'To be, or not to be, that is the question: Whether 'tis nobler in the mind to suffer The slings and arrows of outrageous fortune, Or to take arms against a sea of troubles, And by opposing end them.' Wait, the actual question is: In 'My favorite activity is reading,' what is the function of 'reading'?