Why is it difficult to find the cause of whale death?

B. Listen to the following short statements and then choose one of the answers that best fits the meaning of each statement by blackening the corresponding letter on the ANSWER SHEET. There are 10 questions in this part of the test, 1 point for each question. You will hear each statement only once.
   11. It was not possible to say whether the plastic had caused the whale’s death because of its advanced state of decay, according to the expert.
   12. By the end of 2017, the total number of cars had reached one million on the roads of 53 cities, two million in 24 and three million in seven. The leader was Beijing with the number edging towards six million.
   13. Named "Our 40 Years", the gala was divided into Overture, Part One, Part Two and Epilogue.
   14. Through art forms such as singing, dancing, plays and poetry recitals, the gala gave full
   expression of the determination and confidence of the Chinese people to carry out reform and opening up all the way under the strong leadership of the CPC Central Committee with Xi Jinping at the core.
   15. The paper explains that individuals who are genetically more sensitive to the bitter taste
   of caffeine actually end up liking coffee more than those who aren’t.
   16. He demanded law-based use of public power, closing supervision loopholes, and minimizing the space where power can be exercised at will.
   17. The Chilean President heralded the arrival of the largest pure-electric fleet in Latin America as launching the era of "Third Millennium Transport" that would improve the quality of life for all Chileans.
   18. He also reiterated the dire warning of former American President Barack Obama that, "We
   are the first generation to feel the effects of climate change and the last generation who can do something about it. "
   19. The two leaders also agreed to consolidate their mutual solidarity and support in addressing challenges that their nations face individually and collectively.
   20. They noted that effective regional cooperation is crucial for overcoming the common
   obstacles of insecurity, terrorism, poverty and environmental degradation facing the region.