A woman and her dog walked through the airport, passing by dozens of people. Suddenly the dog _________ without making a sound, it sat like a statue and stared at a man carrying a suitcase.

The woman _________ the man carefully, waiting until he put down the suitcase. Then she shouted, “Police. Don’t make a move!” Other _________ moved in. They quickly _________ the suitcase. The man had been carrying a bomb in it! On the TV news that evening, the _________ was a hero. Thanks to this police dog, something terrible had been _________. Lucky, the police dog, had found the bomb in a way no human ever could. The dog had not _________ or heard the dangerous device inside the suitcase. _________, the animal had found it with its _________. Lucky had smelled the bomb.

A dog can sense odors (气味) that are thousands of times too __________ for people to smell. The part of a dog’s brain that deals with odors is much larger than that __________ part of the human brain. People depend on differences in __________ in order to tell things apart. A dog on the other hand, depends on differences in __________.

Everything and everyone has an odor. That’s why highly trained dogs are often used by the police to __________ people or find drugs. They have been taught to __________ specific smells. The animals’ sense of smell is so powerful that they can even tell if a person has recently touched a certain object.

Many of the different kinds of materials used in bombs give off exactly the same odor. A dog learns to search for it. If the dog finds a bomb, however, it must never __________ it. It must not let the person who is __________ the bomb know. Instead, the dog has been trained to __________. Police officers watch for this __________. Then, when the dog has finished __________ job, police can make their move.

The stress of daily life has given rise to a new phenomenon—sleep texting. People with this condition send text messages while asleep to their friends and family—completely _________ that they are doing it.

Sleep specialist Dr. Cunnington, of Melbourne Sleep Disorder Centre in Australia, said patients had reported _________ of sleep texting -and he has advised people to leave their _________ outside the bedroom.

He said, “We have had patients who have reported sending text messages to their friends and family while asleep. It is one of those things that happens, but it is very _________, and certainly not a common trend.”

Unsurprisingly, there are no _________ into sleep texting—but a _________ phenomenon, sleep emailing, was studied in 2008.

Researchers at the University of Toledo reported the case of a woman, 44, who would _________ e-mails while sound asleep. She had no recollection (记忆) of sending the e-mails when she was awake. Dr. Cunnington said cases of sleep emailing were more common, and were likely to have a more _________ effect on the lives of sufferers.

He said, “Emails can be sent to work colleagues and have much more serious _________, whereas text messages are more likely to be __________ sent to a friend or family member, so people aren’t as likely to complain of a problem.”

Dr. Cunnington described sleep texting as the __________ of people having too much to do during waking life. He explained: People are doing so much during a normal day that it can mean that they feel like they’re “on call” even at night.

“ __________ it’s so easy to receive e-mails constantly, and get notifications (通知) from smartphones, it becomes more difficult for us to ________ our waking and sleeping lives.”

Dr. Cunnington said people __________ to get a quality night’s sleep must realize that the key point is that people need to respect their sleep, and make an effort to __________ at night.