[讨论]大全补充250第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,

此题为何不选B？如果就意思来讲，似乎B较E更接近原题意啊。

E中，MP is cultivated . B中, derivative is cultivated.

请指教。

de·riv·a·tive

adj.

1. Resulting from or employing derivation: a derivative word; a derivative process.
2. Copied or adapted from others: a highly derivative prose style.

1. Something derived.
2. Linguistics. A word formed from another by derivation, such as electricity from electric.
3. Mathematics.
   1. The limiting value of the ratio of the change in a function to the corresponding change in its independent variable.
   2. The instantaneous rate of change of a function with respect to its variable.
   3. The slope of the tangent line to the graph of a function at a given point. Also called differential coefficient, fluxion.
4. Chemistry. A compound derived or obtained from another and containing essential elements of the parent substance.

你能说某种草药种植，不能说，某种化合物种植吧，

就象是你可以种花，但是不能种精油，虽然精油是从植物中提炼出来的。

MP而不是derivative被cultivated,所以Ｂ肯定是错的

呵呵，我对derivative的理解狭隘了