1. Today these observations can seem quite commonplace, yet looking back one must view them as a solid landmark in malaria research.
    现在这些观察看上去好象很平常，然而回首往事时，人们定会把它们视为疟疾研究上一个坚固的里程碑。

2. As we drove along, someone would single out to me a famous building, an important street, a park, a bridge that when built was thought to be a landmark.
    当我们驱车行驶的时候，有人指给我看那些建造时被曾认为是陆上的标志性建筑物：著名大楼、重要街道，公园和大桥。