补充191

191. A substance derived from the Madagascar periwinkle, which has proved useful in decreasing mortality among young leukemia patients, is cultivated in China as part of a program to integrate traditional herbal medicine into a contemporary system of health care.

(A) A substance derived from the Madagascar periwinkle, which has proved useful in decreasing mortality among young leukemia patients,

(B) A derivative, which has proved useful in decreasing mortality among young leukemia patients, of the Madagascar periwinkle,

(C) A Madagascar periwinkle derivative, which has proved useful in decreasing mortality among young leukemia patients,

(D) The Madagascar periwinkle has a derivative which has proved useful in decreasing mortality among young leukemia patients, that（E）

(E) The Madagascar periwinkle, a derivative of which has proved useful in decreasing mortality among young leukemia patients,

答案是e,我错选c, 哎，彻底没头绪了，我怎么知道会是a derivative of Madagascar periwinkle 呢？

c和e是不是只能通过逻辑意思加以区别呢？

kun,

C中“A Madagascar periwinkle derivative”的表达有误

正确的应该是a derivative of the Madagascar periwinkle

这题我也有点困惑---我想是不是只能从逻辑意思上去理解了才能做对题啊？

逻辑意思应该是  ：

Madagascar periwinkle 被cultivated in China.

而 Madagascar periwinkle的萃取物derivative对.....很有用。derivative应该不能被cultivate的吧？

", is cultivated in China as "   requires    "periwinkle"   to be its subject. Only E meets this requirement.

c和e的一个区别可从后看，（）is cultivated in China ，一样东西被种植。The Madagascar periwinkle和 a derivative 比前者更可能被种植，因为M大写表明这是个专有名词，从文中看极有可能是一种植物，而a derivative 衍生物是不能被种植的，只能从植物中提炼。

谢谢楼上三位讲解，kunkun总算明白了