Sort out the characters according their tones.

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
工,大,小,下( choose the first tone):
有,右,左,尖( choose the first tone):
工,中,百,不( choose the fourth tone):
千,有,右,力( choose the thirth tone):