英语翻译
Not a single pebble was found that might have indicated that the pebbles came
from the nearby continent.这里not a single是不止一个还是一个都没找到的意思?第一个that后面的是修饰pebble的定语从句吧?
Until the late 1970s,many scholars didn't believe that...这里可不可以当成not...until句型来翻译?还是把until等同till然后直译（这样有点怪）?如果把它看作not...until句型,为什么不把not提前?