单项选择题

Questions 17 to 20 are based on the following passage. At the end of the passage, you will be given 20 seconds to answer the questions.
Now, listen to the passage.

What is the best definition of the phrase "a game of two halves"

A.A different ball should be used in each half of the match.
B.Anything can happen in football.
C.Players shouldn’t argue with the referee.
D.Each team should use its own ball for part of the match.