19. I had as much fun sailing the seas as I now do with students.
A
working
B
work
C
to work
D
worked
使用非谓语动词作状语，I和work是主谓关系，用现在分词作时间状语。故选A。
句意：我在海上航行和现在和学生一起一样快乐。使用非谓语动词作状语，I和work是主谓关系，用现在分词作时间状语。故选A。
易错选C