And yet the children themselves are only an intermittent presence in these pages, entering as a source of strife and disappearing once the conflict over them is resolved.
然而这些战中的孩子只是断断续续的出现在这本书中：当矛盾来临时他们出现了，当争端解决了他们又消失了。
2
Yet since wind and solar power are intermittent and other technologies are still experimental, a constant source of low-carbon electricity will also be needed.
Now that we have a very intermittent energy source that we want to insert into the grid, we need to rethink how we manage the integration of those resources.