Read the followi...

Câu hỏi: Read the following passage and mark the letter (A, B, C or D) on your answer sheet to indicate the correct answer to each for the question.

A. To explain that not all tides are caused by gravity. 

B. To give an example of an extreme tidal phenomenon

C. To show that they are not related to natural tides

D. To suggest that more categories for tides area needed.