present simple:I build the house.
pr.continues:I am building the house
pr.perfect:I have already built the house
pr.perfect continues:I have been building house for 2 hours
PAST SIMPLE:I built the house.
past.continues:I was building the house at 3 o'clock
past perfect:I had built the house by 7 o*clock yesterday
past perfect continues :I had been building the house