【单选题】In the sentence 'Because humans are at the top of the food chain, they are particularly vulnerable to the effects of nondegradable pollutants.', 'vulnerable' probably means ______.
【简答题】听下面一段材料,回答第1-3题。 1. Where will Mr. Black stay after his arrival? A. At a hotel. B. At the man's house. C. At the woman's house. 2. What will take place that evening? A. Mr. Black's arrival. B. A hotel...