Breakdown of Я не знаю, обманул ли он нас, но это настоящий шок.
это
this / it is
не
not
он
he / it (for a masculine noun) / it (for a neuter noun)
я
I
Questions & Answers about Я не знаю, обманул ли он нас, но это настоящий шок.
Why is ли used here instead of если for the word 'if'?
In Russian, если is strictly used for conditional 'if' statements (like 'If it rains, we will stay home'). When 'if' means 'whether' in an indirect question (such as 'I don't know whether he deceived us'), you must use the particle ли.
Why does ли come after обманул instead of at the beginning of the clause?
The particle ли always comes immediately after the word that is the main focus of the question. Here, the focus is on the action of deceiving, so it attaches directly to the verb обманул. The structure is always '[focus word] + ли + the rest of the clause'.
Since this lesson is about разве and неужели, could we use one of those here instead of ли?
No. The phrase Я не знаю sets up a neutral indirect question ('I don't know whether...'). Разве and неужели express strong surprise or doubt ('Is it really true that...?') and are used in direct questions. They cannot be used as conjunctions to link an indirect question like ли does.
Doesn't настоящий usually mean 'present', as in 'present tense'?