Complex sentence: These early skates were similar to today's inline skates, but they were not very maneuverable; it was very difficult with these skates to do anything but move in a straight line and perhaps make wide sweeping turns.
Split into simpler sentences: These early skates were similar to today's inline skates, but they were not very maneuverable. It was difficult with these skates to do anything but move in a straight line and perhaps make wide sweeping turns.