The correct form is "did convince." In English, when using "did" as an auxiliary verb, the main verb should be in its base form. So you would say, "I did convince him," rather than "I did convinced him."
President Cleveland was convinced (correctly) that annexation was not the will of the people of Hawaii and that the Monarchy should be restored.
All people living in the United States should speak English fluently.
People should speak English because America is such a big and successful country that the language is spreading all across the world. And if you live in a place with many tourists from America, you should learn and know English. It might be hard to learn but it will be worth it.
People should not remove the English language because a lot of people around the world use that language, it is one of the most popular languages in the world and that is why it should not be removed.
English is not the first language of India, and it should not be, because not enough people speak it as a first language.
We failed to completely take over their country. You'd think that only the French would surrender after winning. Oh, and we should have taught them proper English.
English should be learned to be able to communicate better with people. Assuming you already know another language, learning English will make you bilingual which is a good thing to be.
because its what most people know
...that slavery should not be abolish
Common Sense, published in 1776, was written by Thomas Paine. It convinced many Americans that America should separate from Britain and become independent and republican.
Average English people believed that the Puritans and the Pilgrims were overzealous. They believed that the Protestants sects should be driven out of England.