He was watching the match when the doorbell rang.
something continuing before and after another action
She's been getting more and more depressed.
something that is developing
He was picking grapes in France last summer.
something temporary
I was wondering where you'd got to.
something continuing for some time
I'm always losing my glasses.
something happening again and again
He's driving me mad.
something happening before and after a given time
She' s going out with that friend of Mike's now.
something new
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