Tales from the Tardis/Punctuating "however"

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Hi all :)

In what might be the beginning of a series of brief points about grammar and punctuation, today I want to highlight the proper punctuation around the word however. This linking word is always followed immediately by a comma. If it's in the middle of a sentence, linking up two independent clauses, it's always preceded by a semi-colon.

Here are some examples:

wrong right
How long the Doctor has been retired is not indicated, however dialogue between the Doctor and Vastra, and later the Doctor and Clara, suggest he has been living in his "cloud" for some time as of the start of the episode. How long the Doctor has been retired is not indicated; however, dialogue between the Doctor and Vastra, and later the Doctor and Clara, suggest he has been living in his "cloud" for some time as of the start of the episode.
However the Doctor found the second control room, instead. However, the Doctor found the second control room, instead.