题目内容：

动词非谓语、独立主格结构
1.______such heavy pollution already,it may now be too late to clean up the river.
A.Having suffered
B.Suffering
C.To suffer
D.Suffered
2.Finding her car stolen,______.
A.a policaman was asked to help
B.the area was searches thoroughly
C.it was looked for everywhere
D.she hurried to a policeman for help
3.Do let your mother know all the truth.She appears______everything.
A.to tell
B.to be told
C.to be telling
D.to having been told