to tell someone not to worry. I said "no te preocupes," mostly
because my _Big Red Book of Spanish Verbs_ gives that as an example.
However, I wonder why that's correct. I thought that to form the
imperative for tú, you drop the -s of the present tense form. (Indeed,
that's also what the Big Red Book says in its grammar section.) Can
someone explain to me why "no te preocupes" is correct?