Составить все типы вопросов к предложению: the euro was introduced to world financial markets in 1991.

1. Was the euro introduced to world financial markets in 1991?
2. What was introduced to world financial markets in 1991?
3. When was the euro introduced to world financial markets?
What was the euro introduced to in 1991?
What markets was the euro introduced to in 1991?
What financial markets was the euro introduced to in 1991?
What world markets was the euro introduced to in 1991?
What happened to euro in 1991?
4. Was the euro or the dollar introduced to world financial markets in 1991?
5. The euro was introduced to world financial markets in 1991, wasn't it?