TYPICAL ERROR I have really enjoyed watching football on television this year. Especially as this is the first time we have seen it on a 3D screen.
CORRECTION I have really enjoyed watching football on television this year - especially as this is the first time we have seen it on a 3D screen.
EXPLANATION In the example above, the words in the second ‘sentence’ cannot be punctuated as a separate sentence because they do not make sense on their own. They are an afterthought, and so a dash is the most appropriate punctuation to use.
Insert a dash as needed in each of the following sentences to signal an afterthought (and make any other changes necessary to punctuation).