11. In the nineteenth century, Samuel Gridley Howe founded the Perkins School for the Blind, ____ for children in Boston, Massachusetts.

　　(A) that institutes

　　(B) while instituted

　　(C) was an institution

　　(D) an institute

　　12. Early forms of life on Earth, ____ in the absence of oxygen, required elements such as sulfur instead.

　　(A) which lived

　　(B) whose life

　　(C) lived

　　(D) were living

　　13. People in prehistoric times created paints by grinding materials such as plants and clay into powder ____ .

　　(A) water to be added

　　(B) for adding water then

　　(C) and water added

　　(D) and then adding water

　　14.Often very annoying weeds, ____ and act as hosts to many insect pests.

　　(A) that crowd out less hardy plants than goldenrods

　　(B) crowding out less hardy plants by goldenrods

　　(C) the goldenrods crowding out of less hardy plants

　　(D) goldenrods crowd out less hardy plants

　　15. Starting around 7000 B.C., and for the next four thousand years, much of the Northern Hemisphere ____ temperatures warmer than at present.

　　(A) with experience of

　　(B) experienced

　　(C) experiencing

　　(D) experience

　　Keys:

　　1-5: ACCBA

　　6-10: ABBCC

　　11-15:DADDB