问题
单项选择题
After people have learned that magnets attract things, centuries passed______they took note of the fact that magnets sometimes also repel things.
A．before
B．until
C．after
D．since
答案
参考答案：A
解析：直译为：“在他们注意到……这一事实之前已经过了几百年，也就是说，几百年以后才……”全句可译为：“人们早已知道了磁体能吸引别的物体，又过了几百年，才注意到磁体有时也排斥别的物体这一事实。”