Răspuns:
is trying - a temporary current activity
provides - a habitual or long term activity
has experimented - a completed action that occurred at an unspecified time before now
introduced - a completed action or state in the past
(ha)s become - an action that started in the past and is complete in the present
I am going to the market.
Citizens pay taxes.
He has written his papers.
I phoned her.
They have lived there for the past few years.