46. ___
A. To show that enzymes are very effective.
B. To point out that enzymes can sometimes fail to work.
C. To explain what enzymes are made of.
D. To describe different types of enzymes.
47. ___
A. The relationship between painting and sculpture.
B. The ideas behind an artist's work.
C. The practical value of a work of art.
D. The way the eye perceives shape in sculpture.
48. ___
A. It is often displayed outdoors.
B. It does not always represent an object.
C. It is three-dimensional.
D. It is done by relatively few artists.
49. ___
A. To give an example of natural shapes.
B. To describe early sculpture.
C. To illustrate their use as tools.
D. To demonstrate their role as decorative objects.
50. ___
A. They are always made of stone.
B. They are painted in bright colors.
C. They contain moving parts.
D. They make use of holes.
微信支付 
支付宝支付