我觉得不能绝对的说。需要结合语境 一般来说，连接两个并列的主句，需要加逗号 比如： sentence A，and sentence B
但是在GWD 17-Q18中的正确选项 Over the course ofthe eighteenth century, the average output of ironwork tripled as a result ofseveral improvements in blowing machineryand because coal replaced charcoal asthe fuel used in the smelting of iron ore. 没有加逗号，有具体的原因，可以参考我的一篇回贴(第12篇回复)。 也希望您多提意见。作者: gtl0925 时间: 2011-10-29 21:11
主谓宾，and主谓宾。或 主谓宾and谓宾。
插入成分不符合上述规律作者: kelebonnie 时间: 2011-10-30 10:13
谢谢楼上两位作者: Carter3077 时间: 2016-11-27 23:40
那我想问一下这道题的B选项，如果把and前面的逗号去掉可不可以，
By recording the noise of crinkled wrappers as they were slowly stretched out in an otherwise silent
chamber, and then digitizing and analyzing the sound emissions on computers, a team of scientists
found the noise not continuous but consisted of individual bursts or pops just thousandths of a
second long.
(A) digitizing and analyzing the sound emissions on computers, a team of scientists found the noise
not
(B) digitizing and analyzing the sound emissions on computers, a team of scientists found that the
noise was not
(C) digitizing and analyzing the sound emissions on computers, a team of scientists found the noise
not to be
(D) the sound emissions were digitized and analyzed on computers, a team of scientists found that
the noise was not
(E) the sound emissions were digitized and analyzed on computers, a team of scientists found the
noise not to be