Some plant pathologists have turned to genetic engineering to devise new ways
of responding to botanical diseases. In fact, there was one plant pathologist in
particular, William Powell, who teamed up with forest biologist Chuck Maynard
tore store North America's population of American chestnut trees, which was
decimated in the early 1900s by a fungus known as chestnut blight. A fungus, C.
parasitic a, contributes to the growth of cankers on the trees' trunks; these
cankers, in turn, prevent trees from transporting water from their roots to their
branches and leaves. To render American chestnut trees resistant to the blight,
Powell and May nard experimented with altering the genetic makeup of the trees.
The resultant genetically engineered trees are called Darling 4 American chestnut
trees, and during the first 15 week safter infection with chestnut blight, they grow
cankers that are much smaller than those that grow on American chestnut trees.
Which choice creates the most logical transition at this point in the paragraph?
A.NO CHANGE
B. However, plant pathologist William Powell
C. Plant pathologist William Powell, for instance,
D. Subsequently, plant pathologist William Powell
重点单词：
devise [di'vaiz] vt. 设计，发明，遗赠给
restore [ri'stɔ:] vt. 恢复，修复，使复原
population [.pɔpju'leiʃən] n. 人口 ，(全体)居民，人数
statement ['steitmənt] n. 声明，陈述
render ['rendə] vt. 使成为，提供，报答，着色; 执行，实施
resistant [ri'zistənt] adj. 抵抗的，反抗的
genetic [dʒi'netik] adj. 基因的，遗传的，起源的
specific [spi'sifik] adj. 特殊的，明确的，具有特效的
prevent [pri'vent] v. 预防，防止
logical ['lɔdʒikəl] adj. 符合逻辑的，逻辑上的，有推理能力的
答案：C
解析：
Choice C is the best answer because it creates the most logical transition from the preceding sentence's broad statement about plant pathologists turning to genetic engineering and the next sentence's introduction of a specific example of a plant pathologist who is using genetic engineering.