og11-24(og10-39)，老题新问

39. For members of the seventeenth-century Ashanti nation in Africa, animal-hide shields with wooden frames were essential items of military equipment, a method to protect warriors against enemy arrows and spears.

a method to protect
as a method protecting
protecting
as a protection of
to protect
Choice C is best because the participle protecting begins a phrase that explains what the shields did. Choices A and B awkwardly use the singular word method to refer to items of military equipment rather than to the use of such items. Also, a method of protecting would be more idiomatic than a method to protect in A or a method protecting in B. In B and D, as is incorrect; also, a protection in D has no noun for which it can logically substitute. Choice E is incomplete; used to protect would have been acceptable

看了以前NN的讨论贴，都在关心protecting的修饰问题。这里暂且不提。

我想问的是，A应该是同位语吧？为什么不能来补充说明items？看了OG10的解释，好像是说单数名词method不能说明items，这里仅仅是单复数的错误吗？好像大全里就看到过一题是singular word作同位语 来说明前面的复数名词的。

因为同位语是ets很喜欢的用法，所以要搞搞清楚啊～～～

很明确地，请问lz, essential items of military equipment 是 a method或methods吗？

这里protecting作为独立主格成分存在，修饰主句的主语或者整个主句表达的逻辑意思

但是og 关于c的解释是说doing是在修饰items不是整个句子呀！

C Correct. In this sentence, protecting properly introduces a modifying phrase revealing the purpose of the items