Improper prepositions

IF you say “I demand FOR an apology”, your command may fall flat – on your face or the floor – all because of one wrongly used word.

If someone has done you wrong, can you imagine how forceful you can sound if you say: “I demand an apology!” (with the stress on “demand”)? But if you were to say “I demand for an apology!”, you will sound somewhat tame and will also be ungrammatical.