Keep expecting.. It also could be written as this:

Gallia valisi onu durdurmaya çalışsa da başaramadı.*

*( I prefere başaramadı to yenilgiye uğradı in this sentence)      

For expressing real conditions in verbal clauses V + AOR + -se… is used:

Acele et|mez|se|n, treni kaçıracağız. ‘If you don’t hurry…’

When the condition is unreal, se is attached straight to the verb stem V + -se…:

Erken yat|sa|ydı|n, yorgun olmayacaktın. ‘If you slept early…’

Wishes are spoken out with the same formula. 

The above rule has been explained in a hundred threads before. But I still want to make sure how it works in existential (var/yok) and nominal (‘to be’/değil) sentences.

I choose as simple examples as possible:

In other words, when the condition is unreal the verb ol- is called for help.

Have I understood this correct? Are the translations in the table as they should be?

When tense/aspect/modality markers co-occur they appear in the order given below (Göksel – Kerslake). Copular markers (group 4) are composite. They consist of the copula -(y)- < *-i- and the grammatical marker –DI, -mIş or –sA. Copular markers attach to

1. nouns

2. verbs that contain one of the tense/aspect/modality suffixes in group 3

The double role of –sA- attracts attention here. It can occur either in group 3 or as a copular marker. I understand the difference is that of unreal and real conditions. That is why when it attaches to nouns it always denotes a real condition (of course because it is in the position of a copular marker!).