听下面一段独白，回答以下小题。
【小题1】How much may fish in the oceans shrink by in the coming decades?

A．14%.

B．20%.

C．25%.

【小题2】What is the main reason for the decrease in fish size in the oceans?

A．Water pollution.

B．Global warming.

C．Overfishing.

【小题3】How did the researchers feel about the decrease in fish size in the oceans?

A．Angry.

B．Puzzled.

C．Astonished.

【小题4】What should people do to prevent the decrease in fish size in the oceans?

A．Control fishing.

B．Prevent the movement of fish.

C．Stop producing greenhouse gases.