179. During the early years of European settlement on a continent that was viewed as "wilderness" by the newcomers. Native Americans, intimately knowing the ecology of the land. were a help in the rescuing of many Pilgrims and pioneers from hardship, or even death.

(A) Native Americans, intimately knowing the ecology of the land, were a help in the rescuing of

(B) Native Americans knew the ecology and the land intimately and this enabled them to help in the rescue of

(C) Native Americans, with their intimate knowledge of the ecology of the land, helped to rescue

(D) having intimate knowledge of the ecology of the land. Native Americans helped the rescue of

(E) knowing intimately the ecology of the land, Native Americans helped to rescue

the comma required before and in larger compound sentences is omitted.这个

知识点大家谁会呢？斑竹能不能给个以前的N帖子呢 万分感激

B. Native Americans knew the ecology and the land intimately

and this enabled them to help in the rescue of

and 前后是两个完整句子，需要用都好分隔。

那意思是如果and前不是完整句子用逗号分开就是错的了？谢谢啊!!

I think so, unless it is introducing an list.

For example:

I like apples, oranges, and bananas.