Halliday & Matthiessen (1999: 560):
When two figures are linked into a sequence, by some logical semantic relation, there is a rather wide range of possible semantic relations between the two: the relations of time and of cause and condition are particularly elaborated in this respect, but there are others besides — the manner, the matter, and so on. The distinctions among these relationships, however, may be to a greater or lesser degree neutralised, where one clause is construed as dependent on the other; this happens as the dependent clause moves from finite to non-finite status. For example, in they get caught taking bribes the distinction that would be made in the agnate finite clause, among, say they get caught if they take bribes, they get caught when they take bribes, they get caught because they take bribes, is simply neutralised — it is not a blend of all three, nor is there any ambiguity involved.