Page 199, Manhattan SC book, 5th Edition:
Right: By January 2,2000, the so-called "Y2K problem" was already widely considered a joke— although the reason for the non-event was the huge corporate and governmental investment in prior countermeasures.
Question: Could we use colon in place of dash?
Analysis: Perhaps no, because the sentence after dash is not an explanation for the sentence before dash.
Right?