They started with 15 to 40 different pure strains of algae and microscopic animals, and added these one at a time in various combinations and sequences to a large flask.
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美
- 他们从15至40种不同的单一水藻植株和微生物入手,依次把这些物种以不同的组合形式及先后次序放入一个大烧瓶。