branch out (/reason/comprehend) by analogy; draw parallels from inference; grasp a typical example and you will grasp the whole category; single out one thing and bring out its interrelationships
❍ 因此而晓悟了知的，岂只是一种植物的生活史； 生命的秘奥，万物的消息，也将触类而旁通。(叶圣陶《倪焕之》137) Now what they learn from all this is not just the life-history of one species of plant:they can branch out by analogy into the whole mystery of life and a study of all living things.
触类旁通
reason(or comprehend)by analogy;single out one thing and bring out its interrelationships;grasp a typical example and master the whole category
触类旁通chù lèi pánɡ tōnɡ
旁通：互相贯通。指懂得或掌握了某一事物的知识，就可以推知同类的其他事物。reason by analogy, draw parallels from inference, branch out by analogy