It can be inferred from the passage that animals that are prey rarely experience dream sleep because they
A、have evolved further than predators
B、are particularly intelligent animals
C、need less sleep than predators
D、would be caught if deeply asleep
The author states that during dream sleep, the animal sleeps
A、without moving
B、shallowly
C、intermittently
D、on its side
Task 1
16. Paragraph① 17. Paragraph② 18. Paragraph③ 19. Paragraph④ 20. Paragraph⑤ A. Lightening Causes Puzzles to PeopleB. Types of LightningC. Causes of LightningD. Differences Between Thunder and ThunderstormE. Frequencies of Thunderstorms Occurring in the Worldand the U. S. F. Shock Waves as Thunder