1. Almost _________ countries use the decimal system.

(A) all
(B) all of
(C) all of which
(D) of all

2. Alpha rhythm, a brain (A)wave frequency of moderate voltage, is (B)characteristic of a person (C)when is awake but (D)relaxed.

3. Also called the painted cup, the Indian paintbrush gives forth tiny flowers that are mostly green, while ___________________ brightly colored.

(A) its leaves
(B) it leaves being
(C) are its leaves
(D) its leaves are

4. (A)Although absolute zero cannot (B)actually be reached, approximations of (C)less than 0.001 degrees Celsius above absolute zero have been (D)created the laboratory.

5. (A)Although copper was hammered into tools and ornaments (B)by some early inhabitants of North America, the smelting and casting of copper (C)were unknown (D)between them.