7.The first building to employ steel skeleton construction,_____.

(A)Chicago,Illinois,the home of the Home Insurance Company Building completed in 1885.

(B)The Home Insurance Company Building in Chicago,Illinois,was completed in 1885.

(C)Because the Home Insurance Company Building in Chicago,Illinois was completed in 1885.

(D)The Home Insurance Company Building in Chicago,Illinois,in 1885.

8.During the course of its growth,a frog undergoes a true metamorphosis _____ with fishlike larval stage.

(A)begin

(B)began

(C)beginning

(D)is begun.

9.Mahalia Jackson,_____ combined powerfully vitality with great dignity,was one of the best known gospel singers in the United-States.

(A)it was her singing

(B)which songs

(C)who sang

(D)whose singing

10.Precious metals,gems,and ivory have been used to make buttons,but most buttons are made of _____ wood,glass,or plastic.

(A)such materials that

(B)materials as such

(C)such materials as

(D)such materials.

11.Outside the bright primary rainbow,_____ much fainter secondary rainbow may be visible.

(A)so

(B)a

(C)since

(D)still

12.An critic,teacher,librarian,or poet who hopes to broaden poetry's audience faces the difficult challenge of persuading skeptical readers _____.

(A)that poetry is important today

(B)for poetry to be important today

(C)to be important poetry today

(D)poetry that is important today.