>1. There .... (be) lots of complaints about his behaviour since he
>.... (begin) atteding the classes last month. *{have been}, {began}*
>
>2. Nobody .... (pay) any attention to the damaged wiring until one
>member of the staff .... (be) electrocuted last Friday. *{had} paid, was*
>
>3. Brian .... (work) really hard. He used to come back home after
>midnight. *{worked}*
>
>4. I cannot tell you much about this author. I .... (never/read) any
>of his books. *have never read* OK
>
>5. Why don't you switch the alarm-clock off? {It} .... (ring) for twenty
>minutes now. *{has been ringing}*
>
>6. I realised something wrong .... (go on) as soon as I .... (hear)
>these wild screams. *was going on, heard* OK
>
>7. Isn't it high time {you} .... (return) the pliers? You .... (keep) them
>for too long. *{} returned, have {kept}*
>
>8. How often .... (Bill/have to) feed his goldfish? Twice a day. *{does} Bill
>{have} to*
>
>9. We .... (arrange) everything for you by the time you .... (arrive)
>home next Sunday. *will {have arranged}, {} arrive*
>
>10. Don't be afraid. Nothing wrong ..... (happen) as long as you .....
>(obey) all the regulations. *is going to happen, {} obey*