Complex sentence: South Dorset was a staunchly Conservative constituency, and Risdon was defeated by the incumbent, Major Robert Yerburgh, 1st Baron Alvingham; one of the factors contributing to the defeat of Ramsay MacDonald's ten month minority government was the Zinoviev letter.
Split into simpler sentences: South Dorset was a staunchly Conservative constituency, and Risdon was defeated by the incumbent, Major Robert Yerburgh, 1st Baron Alvingham. One of the factors contributing to the defeat of Ramsay MacDonald's ten month minority government was the Zinoviev letter.