Over the course of the eighteenth century which two european powers were locked in almost continual warfare?

The correct answer is - England and France.

England and France have a very long history in engaging into wars between each other. The two powerful Western European countries have had tensions between them continuously for few hundred years. The reasons for the wars between these two countries have been numerous, ranging from territorial to economic ones.

During the 18th century, England and France have been in war for almost the entire century. The wars in the 18th century started at 1702 and continued, with little breaks, up until the end of the century and entering the next 19th century. The winners were constantly changing from battle to battle, with both having success and losses.