[求助]OG FOR VERBAL REVIEW SC- 001

yuanlipinglily

Some bat caves, like honeybee hives, have residents that take on different duties such as defending the entrance, acting as sentinels and to sound a warning at the approach of danger, and  scouting outside the cave for new food and roosting sites.

(A) acting as sentinels and to sound

(B) acting as sentinels and sounding

(C) to act as sentinels and sound

(D) to act as sentinels and to sound

(E) to act as a sentinel sounding

I choose A but the answer is B.  

OG's explaination: The original sentence has an error in parallel structure. It starts by using the -ing(participal) form to list the bats' duties. Defending, acting, and scouting all use the same -ing form. The phrase to sound uses the to-(infinitive) form, and so it is not parallel. The word sounding is required in this sentence.

My understanding: I still don't understand why sound is parallel to defending, acting and scouting because there is and before scouting which means scouting is the last word to paralle. Since there is and before sound, sound can not be parallel. Am I right?.

深秋的马蹄莲

and本身就是平行结构的一个标志，也就是and连接的几个对象必须是平行结构的，要么都是名次，要么都是介词短语，相同功能的从句等等，这里明显的and 连接的都是such as后面的几个动作性的短语，当然要在形式上保持一致阿

yuanlipinglily

and应该用在平行结构中最后一个此前阿

yuanlipinglily

I choose A because I think and to sound is to modify sentinels rather than prallerl to acting and scouting

三脚猫

这题我也想了很久，我觉得关键还是在OG所说的“B uses the correct idiom, and observes the parallelism required among and within the three main verb phrases.也就是说，是三个词组的并列。

yuanlipinglily

Thank you. It'really hard to understand this kind of parallelism.

yuanlipinglily

Thank you. It'really hard to understand this kind of parallelism.