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。”