On a Fly drinking out of his Cup

Busy, curious, thirsty fly! Drink with me and drink as I: Freely welcome to my cup, Couldst thou sip and sip it up: Make the most of life you may, Life is short and wears away. Both alike are mine and thine Hastening quick to their decline: Thine 's a summer, mine 's no more, Though repeated to threescore. Threescore summers, when they're gone, Will appear as short as one!