【英语时差8,16】微生物（上）

When you’re sick, you might casually¹ say, “I’ve got a bug,” or “I think I’ve got some kind of a virus.” Today, most of us take for granted the existence of microorganisms — tiny living organisms too small to be seen with the naked eye. Theories about invisible particles causing disease go back almost two thousand years, but it wasn’t until the late 1600’s that scientists finally saw microorganisms under a microscope and could see that they were alive. The Dutch scientist Antony van Leeuwenhoek was probably the first person to describe the organisms that before had been invisible. Van Leeuwenhoek found these organisms in all kinds of places and called them, “animalcules.” In a letter written to the Royal Society, van Leeuwenhoek described finding thousands of animalcules in his own mouth.

1 casually   

adv.漠不关心地，无动于衷地，不负责任地

参考例句：

• She remarked casually that she was changing her job.她当时漫不经心地说要换工作。
• I casually mentioned that I might be interested in working abroad.我不经意地提到我可能会对出国工作感兴趣。