28. Which of the following can be inferred from the passage about a soil sample with little or no clay in it?
(A) It is not very heavy.
(B) It may not hold its shape when molded.
(C) Its shape is durable
(D) Its texture cannot be classified
29. The word "they" in line 23 refers to
(A) categories
(B) sieves
(C) larger particles
(D) clay particles
30. It can be inferred from the passage that the sediment sieve has an advantage over the hand test in determining soil texture because
(A) using the sieve takes less time
(B) the sieve can measure clay
(C) less training is required to use the sieve
(D) the sieve allows for a more exact measure
31. During the procedure described in paragraph 3, when clay particles are placed into water they
(A) stick to the sides of the water container
(B) take some time to sink to the bottom
(C) separate into different sizes
(D) dissolve quickly
32. The word "fine" in line 24 is closest in meaning to
(A) tiny
(B) many
(C) excellent
(D) various
33. All of the following words are defined in the passage EXCEPT
(A) texture (line 3)
(B) ribbon (line 11)
(C) sediment sieves (line 19)
(D) evaporated (line 27)
参考答案： DAD BCBBD BA