11.___ all this, they made me pay for the damage.

A. Knowing B. Have Knowing C. Known D. To know

12._____such heavy pollution, it may not be too late to clean up the river.

　 A. Having been suffered B. Having suffered

　 C. To suffer D.Suffered

13._____ for half a year, the patient became far better.

　 A. Having been well tended B. Having tended

　 C. Being tended D.Tending

14. The wild flowers looked like a soft orange blanket________the desert.

A.covering B. covered C. cover D. to cover

15. The visiting minister expressed his satisfaction with the talks, _______ that he had enjoyed his stay here.

A. having added B. to add C.adding D. added

16. _______ up at his father, he asked what was the matter with him.

A. Having looked B. Looking C. To look D. Look

17. ________ from his clothes, he is not so poor.

A. Judged B.Judging C. To judge D. Having judged

18. Hill often attends public lectures at the University of London chiefly______ his English.

A. to improve B.improving C.to have improve D. improved

19. Every day the boy, together with his classmates, ________ to go to the sports ground and ________ football, _________ themselves.

A. are noticed; play; enjoying B. is noticed; plays; enjoying