Field 3: STR vs BAS:
STR differs from BAS only in the negative forms of auxiliaries and modals. For other POSs, only uninflected forms are included in the STR field. The following are the only lines on which STR and BAS differ:
E0012152|be|aren't|aux|negative|
E0012152|be|isn't|aux|negative|
E0012152|be|wasn't|aux|negative|
E0012152|be|weren't|aux|negative|
E0014877|can|can't|modal|negative|
E0014877|can|cannot|modal|negative|
E0014877|can|couldn't|modal|negative|
E0020796|dare|daren't|modal|negative|
E0023651|do|didn't|aux|negative|
E0023651|do|doesn't|aux|negative|
E0023651|do|don't|aux|negative|
E0030899|have|hadn't|aux|negative|
E0030899|have|hasn't|aux|negative|
E0030899|have|haven't|aux|negative|
E0039142|may|mayn't|modal|negative|
E0039142|may|mightn't|modal|negative|
E0041474|must|mustn't|modal|negative|
E0044483|ought|oughtn't|modal|negative|
E0055547|shall|shan't|modal|negative|
E0055547|shall|shouldn't|modal|negative|
E0065450|will|won't|modal|negative|
E0065450|will|wouldn't|modal|negative|
Field 5: NEG
The negatives are negative and broad_negative. They are each discussed below: