I sometimes come across some texts where the preposition "for" is used to explain reasons. For instance:
- "And K. shook him by the hand, which seemed obviously to surprise him, for he had been going to content himself with a bow."
- "You must let me take your arm, for you are surer of foot than I am."
I have some questions:
- Is this usage common nowadays, or is it outdated? (Both shown examples are from a novel traduced from German to English in 1930).
- Is it more or less formal than "as", "since", and "because"?
- Is it more used in British or American English?
- Finally, how can I apply it correctly so that the sentence is not misunderstood?