They had just had enough time to swim out of danger when the boat again completed a circle. 这句话为何是again completed,不应该是completed a circle again吗?again修饰动词不是放后面吗?
again 并不是像你理解的那样只能放在句末。again 可以坐落于句首,句中。只是最常见的是坐落于句末。比如:
I visited Beijing again. 普通说法。
Again I visited Beijing. 强调again。
I again visited Beijing. 强调Beijing,again坐落于主谓之间。