Martin (1992: 220):
The following examples bring out the continuity between alternation and retracting or contrastive opposition depending on whether alternatives are viewed as one or the other, one instead of the other or one as opposed to the other.
[ALTERNATION][4:139] We might argue that it's a Range. 'a or b'Or it might be Goal.
[RETRACTION][4:140] We might argue that it's a Range. 'a in place of b'Instead, it might be Goal.
[CONTRAST][4:141] We might argue that it's a Range. 'a different from b'In contrast, it might be Goal.
 These are misconstrued as internal relations. In each case, the conjunctive relation is with the figure realised by the projected clause, not with the enactment of the proposition it realises.
 The "continuity" that Martin recognises here between his categories — alternation within additive, and retraction and contrast within comparative — is actually the fact they are all, logically, types of extension. In SFL theory, these three texts exemplify three types of cohesive conjunction:
- extension: variation: alternative, meaning X or Y
- extension: variation: replacive, meaning not X but Y
- extension: addition: adversative, meaning X and conversely Y
 Logically, only the first text involves alternatives.
 This confuses adversative (extension: addition) with comparison (enhancement: manner).