3. The airport security guard knew that he could of scored a fingernail clipper from the rock star, who ironically enough was a strong believer in personal hygiene.

Ans.

3. The airport security guard knew that he could have scored a fingernail clipper from the rock star who, ironically enough, was a strong believer in personal hygiene.

1) The correct phrasing is "could have" even though when we speak this, it sounds like "could of." [1pt.]

2) There is no comma after "star" because the relative clause "who was a strong believer in personal hygiene further identifies which rock star. It is a restrictive relative clause because it restricts the meaning of rock star to a particular rock star. [1 pt.]

3) Use commas to set off "ironically enough" because it is a parenthetical element. [2 pts.]

Total = 4 pts.