Halliday & Matthiessen (2014: 413-4, 416):
Experientially, a phrasal verb is a single Process, rather than Process plus circumstantial element. This can be seen from their assignment to process types. For example, the verb see represents a mental process, and so has simple present as its unmarked present tense, as in do you see that sign? (not are you seeing that sign?). But see off is material, and so has present in present: are you seeing your brother off? (not do you see you brother off?, which can only be habitual). The transitivity analysis is therefore as in Figure 6-20.
