Which of the following countries are members of the Commonwealth?
The Commonwealth is a voluntary association of 56 independent and equal countries, almost all of which were formerly part of the British Empire. It's rooted in history, dating back to the early 20th century as the Empire evolved. The key is that these nations share historical ties to Britain. Bangladesh, India, South Africa, and the UK all fit this bill. India gained independence in 1947, South Africa was a founding member in 1931 (rejoining in 1994 after apartheid), and Bangladesh joined in 1972 after its independence. The UK, of course, is at the heart of the Commonwealth. Countries like the Czech Republic, Germany, Poland, and Spain, on the other hand, have no historical connection to the British Empire and therefore aren't members. So, remembering the historical link to the British Empire is the key to identifying Commonwealth members.
Think of cricket matches under commonwealth nations, like India, Bangladesh, South Africa, and of course, the UK. That's your commonwealth quartet.