Halliday & Matthiessen (2014: 620):
Conditionals subdivide into (i) positive, (ii) negative and (iii) concessive. Examples:
(i) positive:[S02:] ||| That’s the DEET account. ||| Well there must be more money coming from that. ||| Do they tend to pay – || how do they – ||| – [S04:] ||| Per issue. ||| – [S02:] ||| Per issue. ||| Well in that case do they pay after the issues come out? |||
(ii) negative:||| “I mustn’t say anything about it. ||| Otherwise, I’ll get shot by the lady [[ who just shut the door]] ,” || Holm said, || referring to a publicist [[ who had just left the room]] . |||
(iii) concessive:||| The outstanding performance of U.S. and other NATO military units has enabled SFOR to fulfil the military tasks [[spelled out in the Dayton Accords]] . ||| Nevertheless, success [[ in achieving the civil, political, and economic tasks [[ identified at Dayton]] ]] has been slower in coming. |||