一.Such sentences do not always occur in thinking, and when they do they are merged with vague imagery and the hint of unconscious or subliminal activities going on just out of range.二. Thinking, as it happens, is more like struggling, striving, or searching for something than it is like talking or reading. Words do play their part but they are rarely the only feature of thought.  

“and when they do they”,as it happens这是什么句式？是什么意思？going on just out of range是什么意思？是短语吗？do play their part是什么意思？rarely，only 在该句中是什么意思？