Use of English PRO

The (0) MODERN European alphabet is based (1) ............ the Greek and (2) ............ to other European countries under the Romans. A number of changes took (3) ............ as time (4) ............. The Romans added the letter G, and the letters J and V were (5) ............ to people in Shakespeare's time. If we (6) ............ the history of punctuation, we also find some interesting facts.The Romans used to write a question at the end of a sentence in (7) ............ to show that it was a question. They started to write Qo in (8) ............ of the whole word, and then put the Q above the o. In the end, that became the question mark'?'.