请问这是个什么句子 and hence后为什么主谓都省略了? and hence中的and和谁是并列关系?
Under modern conditions,this requires varying measures of centralized control and hence the help of specialized scientists such as economists and operational research experts.
and是并列连词,hence 是副词(因此,= for this reason),其后承前省略了this requires。
Under modern conditions, this requires varying measures of centralized control and hence the help of specialized scientists such as economists and operational research experts.
=Under modern conditions, this requires varying measures of centralized control and hence this requires the help of specialized scientists such as economists and operational research experts.
句子的基本结构是:=Under modern conditions, this requires ... and hence this requires... 在现代条件下,这需要……因此它也需要……