I've been enthusiasming you've been enthusiasming he's been enthusiasming we've been enthusiasming you've been enthusiasming they've been enthusiasming
I'll be enthusiasming you'll be enthusiasming he'll be enthusiasming we'll be enthusiasming you'll be enthusiasming they'll be enthusiasming
Future perfect
I'll have enthusiasmed you'll have enthusiasmed he'll have enthusiasmed we'll have enthusiasmed you'll have enthusiasmed they'll have enthusiasmed
Future perfect continuous
I'll have been enthusiasming you'll have been enthusiasming he'll have been enthusiasming we'll have been enthusiasming you'll have been enthusiasming they'll have been enthusiasming
I'd be enthusiasming you'd be enthusiasming he'd be enthusiasming we'd be enthusiasming you'd be enthusiasming they'd be enthusiasming
Past
I'd have enthusiasmed you'd have enthusiasmed he'd have enthusiasmed we'd have enthusiasmed you'd have enthusiasmed they'd have enthusiasmed
Past continuous
I'd have been enthusiasming you'd have been enthusiasming he'd have been enthusiasming we'd have been enthusiasming you'd have been enthusiasming they'd have been enthusiasming