最近看到一句话
“Both automobiles and bicycles offer a convenient means of public conveyance,
with one of the marked differences between the two centered on pollution caus
ed by the former.”
句中动词应该是offer；
然而后面with开始又接了一个centered ，这样句子不就有两个动词了？
（最后一个动词Caused 应该为形容词子句简化而来）