1. This method has never been used in clinical practice.
2. This grammar rule had to be used in translating this sentence into Russian.
3. The patient had been examined by the doctor before the results of his analyses were known.
4. This doctor has been working in the clinic for ten years already.
5. My friend has never been to Moscow
6. The doctor has been examining an X-ray film for several minutes already when somebody entered the room.
7. The experiment was said to have been finished several days ago.
8. The results of the study have been reported already.
9. The nurse had met this condition in her practice before she began to work in this clinic.
10. The experiment could have been over already.
11. The doctor had been examining his patient for half an hour when the nurse entered the room.
12. This method has been developed in our clinic.
13. The operation is known to have been performed by our best surgeon.
14. The patients will have been examined by the doctor before the professor comes.
15. No cases of poliomyelitis have been reported in Finland during the last two decades.
16. Since the times of Hippocrates, fever has been recognized as a hallmark of disease.
17. The patient had had all the signs of acute hepatitis when he applied for the doctor’s help.
18. Thirty to sixty per cent of patients have no symptoms of the disease at the time of examination.
19. Interferon has the capacity to stop the development of some diseases in the human body.
20. He is known to have never been to London.