例：OG10-39 For members of the seventeenth-centuryAshanti nation in Africa, animal-hide shields with wooden frames were essentialitems of military equipment, a method to protect warriors against enemyarrows and spears. A. a method to protect B. as a method protecting C. protecting D. as a protection of E. to protect
答案C。
OG关于D的解释不懂：D。Beginningthe phrase with as is incorrect; using the noun form protection createswordiness 。 as作介词用表示作为不可以么？ | 
