A micro-organism is a very small living thing which you can only see if you use a microscope.
英汉词典释义
n.
微生物
The diseased tissue can be easily invaded by these microorganisms.有病的组织容易被微生物侵袭。They act at least a temporary block to DNA synthesis in microorganisms.它们在微生物中至少对DNA合成起暂时性的阻止作用。