According to the passage, how many major networksare there?
A、Two.
B、Three.
C、Four.
D、Five.
Task 221. Some form of ideal society is22.Books written by J. Verne are23.Peopleenjoy24 Works of modern science fiction have25.Writers find it difficultA. a recurrent themeB. to keep ahead of scientificadvancesC. reading books of science fictionD. political implicationsE. a current themeF. read worldwide