修饰语之间的temporal relationships是怎么回事？

sabriye

178.
                In the last few years, the number of convicted criminals given community service sentences, which allow the criminals to remain unconfined while they perform specific jobs benefiting the public, have risen dramatically.

(A) sentences, which allow the criminals to remain unconfined while they perform specific jobs benefiting the public, have

(B) sentences, performing specific jobs that benefit the public while being allowed to remain unconfined, have

(C) sentences, performing specific jobs beneficial to the public while they are allowed to remain unconfined, have

(D) sentences which allow them to remain unconfined in their performing of specific jobs beneficial to the public has（E）

(E) sentences allowing them to remain unconfined while performing specific jobs that benefit the public has

At issue in this question is subject-verb agreement; the number... has risen must be the kernel of the main clause. Choice E, the best answer, uses a singular verb form, has, to agree with the singular subject, the number. Choices A, B, and C mistake criminals for the sentence subject and so incorrectly use the plural verb form have. In B and C the verb phrases (performing... ) do not clearly modify criminals, because another noun (sentences) intrudes, nor do the verb phrases clearly establish temporal relationships among events. D is wordy and imprecise (in their performing of specific jobs).

这题的temporal relationship我不太明白是什么意思，就仅仅指BC先说了performing后说了allowed这样的先后顺序么？还是指现在分词时间上要比主句提前？

sabriye

自己顶啊，都没人看看啊