<閱讀測驗>[題組:第40-43題]42. According to the passage, which of the following statements is true? (A) PCBs are often used in making electronic products. (B) Chemicals washed down to the ocean stay on the surface. (C) The deepest point of the Mariana Trench is free from pollution. (D) A robotic vehicle was used to help study pollution in the Mariana Trench.
