conjunctive adverb with comma and semicolon

0Hi,02br
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00Usually a semicolon is used to with two independent clauses when a conjunctive adverb is used. Good. But I feel the two independent clauses can be independent in structure but cannot be independent in thought linkage -- that is, they have to related in thoughta and ideas. Am I right? I think I am right because I found some online references supporting it. 02br
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00What is confusing is when what looks to be two independent clauses in structure is connected by a comma, rather than a semicolon.02br
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00The average bamboo floor costs about $5 to $7 a square foot, not including installation01u00, whereas02u00 01font00walnut or pine can cost nearly $10 a square foot02font00.02br
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00I feel that the color part can be said to be an independent-in-structure clause, but I could be wrong. Why did the person write it as this with a semicolon?02br
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00The average bamboo floor costs about $5 to $7 a square foot, not including installation;01u00 whereas02u00 01font00walnut or pine can cost nearly $10 a square foot02font00.02br
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00Should they in semicolons or in separate sentences and not commas? How can I know?02br
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001. This task requires cooperation among members01u00, similarly02u00 it could be said that it requires dedication.02br
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002. He was poor01u00, therefore02u00 it was hard for him to buy basic necessities.02br
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003. Give him a break. He was busy at that time01u00, moreover,02u00 he was sick to really pay attention to what he was doing. 02br
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004. He was poor01u00, neverthless02u00 he gave the poor man the money.0-