作者：英吉
Broccoli thrives in moderate to cool climates and propagated by seeds, either sown directly in the field or in plant beds designed for producing transplants.
(A) propagated by seeds, either sown directly in the field or in plant beds designed for producing
(B) propagated by seeds, sown either directly in the field or sown in plant beds designed so as to produce
(C) is propagated by seeds either sown directly in the field or in plant beds designed so that they produce
(D) is propagated by seeds sown either directly in the field or in plant beds designed to produce
(E) is propagated by seeds, sown either directly in the field or sown in plant beds designed for producing
原文意思：说一个东西thrives并且propagated，说着在field里面sown里了或者在plant beds里面也sown了。
题目分析：原文体现出来了两个并列关系：一个是thrives和propagated的并列，这个并列要想满足后面就必须is否则后面就和前面的thrives这个动词不对应了，我们先把AB干掉。CDE用后面那个并列，就是在field里和在plant beds里sown并列，前后两个地方并列的只有D。
