rather

*I wrote x.  Should I rather write y?

A common mistake for German learners.  When rather  means 'instead' it has to be separated from the rest of the sentence by a comma (two if it comes in the middle of the sentence):

Rather, should I write x?

or

Should I write, rather, x?

This meaning is different from I rather like him meaning 'I sort of like him.'  Would rather meaning 'prefer' takes no commas.