Martin (1992: 230):
[4:162] CONJUNCTION Ben is here.Still I wonder if Flo is coming.
CONTINUITY Ben has left.But Flo is still here.
Blogger Comments:
[1] The function of still is ambiguous here.  It is conjunctive only if its meaning is similar to 'yet':
Ben is here. Yet I wonder if Flo is coming.
| 
still ('yet') | 
I | 
wonder | |
| 
conjunctive Adjunct | 
Subject | 
Finite | 
Predicator | 
| 
Mood | 
Residue | ||
However, if the clause is a textual agnate of:
Ben is here. I still wonder if Flo is coming.
| 
I | 
still | 
wonder | |
| 
Subject | 
mood Adjunct: temporality | 
Finite | 
Predicator | 
| 
Mood | 
Residue | ||
then still is functioning as a mood Adjunct of temporality (see Halliday & Matthiessen 2004: 128), and does not mark a relation of conjunction with the previous message.
| 
still | 
I | 
wonder | |
| 
mood Adjunct: temporality | 
Subject | 
Finite | 
Predicator | 
| 
Mood | 
Residue | ||
[2] The function of still here is interpersonal: a mood Adjunct of temporality, and so it does not mark a logical (for Martin) relation of continuity.
 
| 
but | 
Flo | 
is | 
still | 
here | 
| 
Subject | 
Finite | 
mood Adjunct: temporality | 
circumstantial Adjunct | |
| 
Mood | 
Residue | |||
 
