beginnen vs. anfangen
Is there any difference between beginnen and anfangen? Duolingo teaches the first one here, and I was taught the second one.
So I think 'beginnen' is rather used for things and 'anfangen' for persons' activities. I would rather say "Ich habe zu rauchen angefangen." (I've started smoking) instead of "Ich habe zu rauchen begonnen." and also rather "Der Krieg hat begonnen" (The war has begun) instead of "Der Krieg hat angefangen". But i think it's not really wrong to exchange them.
Shouldn't that be: Ich habe angefangen, zu rauchen ? I don't believe you can put the "zu" phrase in the middle of a clause.
I don't believe this is correct.
'zu rauchen' is an infinitive clause. Normally it would be at the end - although the comma is unnecessary as there is no object.
There are apparently times, however, when it can be inserted into the main clause. Hammer's 4th Ed discusses such enclosed infinitive clauses in 13.2 as and indicates that it is often done with the so called 'semi-auxiliary verbs', such as wissen, suchen, stehen etc. It also indicates that it can also, optionally, be done with other verbs and one example given is, in fact, anfangen.
I suspect that 'Ich habe angefangen zu rauchen' is probably a lot more common but, based on what Hammer's says, it would seem that 'Ich habe zu rauchen angefangen' is probably also correct.
Beginnen tends to be written and a bit more formal, anfangen tends to be spoken and a bit less formal, but there is a lot of crossover. That is what I noticed anyway. Could be wrong and am never offended by a native speaker correcting me.