How much do they spend on design development every year?
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1.Do the drawings on the walldescribe how each process goes on to the next?
How many workers are there on the assembly line?
What does a worker usually do on the assembly line?
柱色谱和薄层色谱都属于（）色谱
A. 吸附色谱
B. 离子交换色谱
C. 凝胶色谱
D. 亲和色谱
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