Dogs can be trained to use their sense of smell to recognize illegal drugs and explosives. So Mark Ruefenacht wondered if the animals could also recognize changes in the blood sugar level of people with diabetes（糖尿病）.

Ruefenacht has had the disease for much of his life. In 1999, he almost died while training a young dog to be a guide dog for the blind. Without any warning, his blood sugar suddenly dropped to a dangerously low level. Luckily, his dog stayed with him, and tried to keep him awake. Finally, he was able to get his blood sugar up. This made him wonder if dogs could be trained to identify the chemical changes that happen during an attack, and then inform their owners.

To train the animals, Ruefenacht uses bottles containing swabs of sweat from a diabetic with low blood sugar, and containers of other smells, such as peanut butter, dog food, or plants. The dogs are given a treat when they choose the correct jar.

This “sweat jar” method for training diabetes detection dogs has been approved scientifically.

The next step is to teach the dog to alert the owner. The dogs are trained to use subtle（细微的）signs at first. However, if those signals are ignored, the animals then put their paws on the owner’s legs or shoulders. They learn to lick and put their nose in the owner’s face, and make noises. If none of these methods work, the dogs are then trained to find someone else to help.

Ruefenacht says the dogs can often detect blood sugar dropping long before electronic systems send a warning sound.

His group, Dogs4Diabetics, has placed more than 100 dogs with diabetics. The group hopes to expand the program — training people’s “most loyal friend” to save lives and help diabetics around the world.

【小题1】What inspired Ruefenacht to train dogs to detect blood sugar dropping?

A．His own near-death experience.

B．The success in training guide dogs for the blind.

C．Dogs’ loyalty to their owners.

D．Dogs’ ability to get blood sugar up.

【小题2】To train the dogs, what did Ruefenacht do?

A．He rewarded the dogs if they made the correct choice.

B．He tested the swabs of sweat from a diabetic with low blood sugar.

C．He proved the “sweat jar” method in a scientific way.

D．He first trained the dogs to know about blood sugar.

【小题3】What is the last but two paragraph mainly about?

A．The process of training the dogs.

B．The ways for dogs to inform their owners of blood sugar dropping.

C．The methods dogs learn to identify low blood sugar.

D．The result of the training.

【小题4】What can be inferred from the passage?

A．Training dogs to help diabetics has been expanded around the world.

B．Dogs are far more advanced in detecting blood sugar dropping than electronic systems.

C．Dogs do make a big difference in many fields to help human beings.

D．Dogs can detect blood sugar dropping by tasting sweat from a diabetic.