取供试品0.2g，加水20ml使溶解，分取10ml，加三硝基苯酚试液10ml，即生成沉淀，滤过，沉淀用水洗涤，在1
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取供试品0.10g，加无水乙醇5ml溶解后，加二苯胺试液1滴，用硫酸铈滴定液(0.01mol/L)滴定，不得超过1.0mlE．
All of the following are mentioned in the discussion of lichens EXCEPT ______.
A. They are capable of producing their own food.
B. They require large amounts of minerals lo prosper.
C. They are a union of two separate plants.
D. They can live thousands of years.
The word "them" in line 7 refers to ______.
A. Sumerian, Akkadian, and Babylonian
B. bilingual inscriptions
C. cuneiform. tablets
D. scholars
The word “fortuitous” in line 6 is closet in meaning to ______.
A. important
B. sudden
C. early
D. lucky
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