Table 4.2 is not an exhaustive classification of MSAs, as indicated by the dots.This means that at the clausal level MSAs can be further divided along the lines of realization and delicacy (cf.Halliday, 1984; Halliday & Matthiessen, 1999).Furthermore, the division of MSAs at the clause-oriented and predication-oriented levels gives birth to more MSAs functioning for different purposes.
Some new MSAs could come into being, when adverbs are placed in the semantic atmosphere of MVs.They are called MSAs rather than MAs, because they do not function as MAs when occurring individually without the co-occurrences of MVs.According to Whorf (1956: 88ff）[cited from Halliday & Matthiessen (1999: 26-27)], the MSAs resulting from the parasitic relationship can be taken as covert categories.These adverbs normally cannot express modality, but they do under the circumstances of parasitic relationships.
Two sub-situations of MSAs are worth noting as far as the parasitic relationships at the clause level are concerned:
A.adverbs that normally do not function modally, especially conjuncts, when serving as MSAs, can indicate such semantic categories as “addition” (e.g.also, as well), “inference” (e.g.therefore, henceforth), and “contrast” (e.g.nevertheless, nonetheless).In this sense, the conjuncts become adjuncts, and function modally because of the impacts of the MVs concerned.
B.the same MSAs co-occurring with different MVs may yield different modal meanings collectively, so may different MSAs co-occurring with the same MVs.
Table 4.2 Classification of MSAs at the clause level
Semantic levelCategorySubcategory
clause-oriented (including disjuncts and some adjuncts converted from conjuncts)declaration (e.g.sure, naturally)negotiability (e.g.clearly, plainly)
non-negotiability (e.g.doubtless, inevitably)
prediction (e.g.predictably, unsurprisingly)predictability (e.g.predictably)
non-predictability (e.g.surprisingly)
presumption (e.g.arguably, supposedly)evidentiality (e.g.allegedly, supposedly)
argument (e.g.arguably, presumably)
desirability (e.g.fortunately, sadly)expectedness (e.g.luckily)
non-expectedness (e.g.unfortunately)
……
predication-oriented (including some adjuncts and MAs)temporality (e.g.eventually, soon)future (e.g.soon)
past (e.g.just, once)
present (e.g.no longer, still)
modality (e.g.probably, necessarily)probability (e.g.possibly, certainly)
usuality (e.g.always, usually)
obligation (e.g.necessarily)
inclination (e.g.willingly, readily)
……
For instance:
(120）…whereas a satisfactory level of information on the trading of goods between Member States should thus be ensured by means other than those involving…
(121）They conceivably might consider their available options now.
(122）She conceivably will be attending the meeting.
In Example (120), the MSA thus denotes a binding effect of law resulting from the contract involved, and is context-sensitive, for its modality is related to the clause as a whole; it strengthens or justifies the attitude conveyed by should.Example (120）shows the birth of clause-oriented MSAs.In Examples (121）and (122), conceivably co-occurs respectively with might and will.It is known that might and will display different modal values in SFL: low and median respectively.Therefore, although both conceivably might and conceivably will express “prediction” (modalization), the latter is more certain than the former. Examples (121）and (122）demonstrate the workings of predication-oriented MSAs.
4.1.2 Parasitic relationships at the discourse level
MSAs occur at the discourse level because of the parasitic relationships as well.Halliday (1994: 324）states that conjuncts as a means of elaboration do not simply restate the elaborated elements but reinstate, summarize, clarify them for the purposes of the discourse.This means that conjuncts are not just textual; under some circumstances, for instance, when placed after MVs in modality supplementing patterns, they could play the interpersonal roles of expressing attitudes or judgments as well.Thus, conjuncts like henceforth, also, and still can convey modality and become MSAs when placed after MVs (e.g.could still, must henceforth, and should also).The reason for these conjuncts to become modally colored is that they have the semantic potentials for conveying modality.Similar situations occur with conjuncts of extension or enhancement (e.g.moreover, also, yet; still, yet, nevertheless).Conjuncts in this sense become adjuncts.As a result, both MSAs and MAs denote modality, but the former outnumber the latter because of the parasitic relationships between MSAs and MVs.
Portner (1993）(cited from Roberts, 1996: 243）uses the term “modal force” to explain the workings of modality, holding that modal context determines the domain of the modal force.This is similar to the occurrences of such new modal devices as MSAs as well as the differentiations of collective modal meanings resulting from the synergic effects of MVs and MSAs.
The parasitic relationship between MSAs and MVs may also yield an interesting phenomenon, i.e.the occurring frequency of some collocations.Paradis (2003）studies some collocations between adverbs and MVs, and finds that can’t really and will really occur frequently.Mitchell (2003）discovers that may as well and might as well are frequent collocations.There are of course some other frequently-occurring collocations in discourse that await people’s finding.
4.1.3 Rhetorical structure
According to Mann & Thompson (1983: 3-9）(cited from Cap, 2002: 47-49), there are 15 kinds of relational propositions in the Rhetorical Structure Theory (RST), important for discourse analysis, listed as follows:
a.Solution
b.Evidence
c.Justification
d.Motivation
e.Reason
f.Sequence
g.Enablement
