1) Present Simple, Passive Voice, простое предложение, основа - Traffic differs. 2) Present Simple, Active Voice, простое предложение, основа - they keep. 3) Present Simple, Active Voice, простое предложение, основа - people say. 4) Present Simple, Active Voice, простое предложение, основа - one can see. 5) Present Simple, Passive Voice, простое предложение, основа - omnibuses are called. 6) Present Simple, Passive Voice, простое предложение, основа - underground is called.