microscopic

/ˌmaɪ.krəˈskɑː.pɪk/
extremely small and difficult or impossible to see without a microscope 极小的；微小的；需用显微镜观察的
a microscopic creature/particle
微生物；微粒
(humorous)
The sandwiches were microscopic!
这些三明治小得都快看不见了！