A．sing in a louder voice

　　B．sing longer

　　C．travel in smaller groups

　　D．get nearer to each other

　　B　[细节理解题。由第五段可知，因为受噪音干扰，现在虎鲸"唱"的时间比原来长。]

　　3．Scientists believe that killer whales sing to ．

　　A．warn each other of dangers

　　B．keep in the same group

　　C．send useful information

　　D．enjoy themselves

　　C　[细节理解题。文章倒数第三段有说明，虎鲸"唱歌"是为了交流捕食或繁殖信息。]

　　4．From the passage，we can feel that the author is ．

　　A．angry　　　　　 B．hopeful

　　C．worried D．disappointed

　　C　[推理判断题。文章介绍观鲸船的噪音给虎鲸的交流造成了困难，从文章最后的叙述看，虎鲸数量在下降，而科学家也不明白其中的原因，因此显然作者对虎鲸的生存状况感到"担忧"。]

　　IV.完形填空

　　If you are human you can't help but experience times when everything seems to be going wrong.You must also 1 as if your life is completely out of control at times.It is during those "down times" that words of encouragement from family，friends，co­workers or 2 strangers can boost (增强) your spirits.It is also during those 3 that destructive words can be devastating (毁灭性的) and sink you deeper and deeper into depression.

For example, consider this story about a group of 4 who were traveling through the woods when 5 of them fell into a deep pit (坑)．All of the other frogs gathered