do---have done
be---have been
in several minutes(seconds/hours)
at times
once/twice/three times a week
sooner or later
after 3 years
right now
just now
as soon as possible
at once
do---have done
be---have been
in several minutes(seconds/hours)
at times
once/twice/three times a week
sooner or later
after 3 years
right now
just now
as soon as possible
at once