Lexis Vs Function Structure: Crocodile Feed

the crocodiles	were feeding
Actor	Process: material

the tourists	were feeding	the crocodiles
Initiator	Process: material	Actor

the tourists	were feeding ('giving')	the crocodiles	chicken
Actor	Process: material	Recipient	Goal

the crocodiles	were feeding on ('eating')	the tourists
Actor	Process: material	Goal

Existential Road Sign

left lane	ends
Existent	Process: existential

Reasoning:

From above (semantics), the meaning being realised isn't a 'doing-&-happening', so not material.

From below (group rank), the simple present tense isn't marked, carrying the feature 'habitual', so not material.

From roundabout, the clause is agnate with there will no longer be a left lane, so existential.

'No More Than' Serving As Mood Adjunct

even	the best of our models	are	no more than	aids to the imagination
mood Adjunct: intensity: counterexpectancy: exceeding	Subject	Finite	mood Adjunct: intensity: counterexpectancy: limiting	Complement
Mood				Residue

Halliday & Matthiessen (2014: 153):

There are two lexical verbs in English, be and have, where, strictly speaking, the simple past and simple present forms consist of Finite element only, rather than of a fusion of Finite with Predicator. This is shown by the negatives: the negative of is, was is isn’t, wasn’t — not doesn’t be, didn’t be.