I left out these other statements.Thank you very much.

Question

1) n 1936 Orwell took part in the Spanish Civil War (Better: he reported about the Spanish Civil War)
2) He resigned the BBC in...
Eton had a hard discipline, according to which teachers used to humiliate students in public, especially in their bare posterior.

Answer 1

1) In 1936, Orwell took part in the Spanish Civil War and then wrote about his experiences.

2) He resigned from the BBC in...

Eton had strict discipline, according to which teachers used to humiliate students in public, especially on their bare backsides.

(You could also use "harsh" in place of "strict.")