1. There ARE lots of complaints about his behaviour since he HAS BEGAN attending the clases last month.
2. Nobody PAYED any attention to the damaged wiring until one member of the staff HAS BEEN electrocuted last Friday.
3.Brian WORKS very hard. He used to come back home after midnight.
4.I cannot tell you much about this author. I HAVE NEVER READ any of his books.
5. Why don`t you switch the alarm-clock off? It HAS BEEN RINGING for twenty minutes now.
6. I realised something wrong GOES ON as soon as I HEARED these wild screams.
7. Isn`t it high time you RETURN the pliers?
8. How often HAS HE HAD TO FEED HIS GOLDFISCH? Twice a day.
9. We WILL HAVE ARRANGED everything for you by the time you ARRIVED home next Sunday
10. Don`t be afraid. Nothing wrong HAPPENS as long as you OBEY all the regulations.