题目内容：

Human’s invention of zero was very important for modern mathematics and science, but we’re not the only to consider “nothing” a number. Parrots and monkeys understand the concept of zero, and now bees have joined the club, too.

Honey bees are known to have some number skills such as the ability to count to four, which may occur when following landmarks in their environment To se whether these abilities extended to understanding zero, researchers trained 10 bees to identify the smaller of two numbers. Across a series of trials, they showed the insects two different pictures displaying a few black shapes on a white background. If the bees flew to the picture with the smaller number of shapes, they were given delicious sugar water, but if they flew toward the larger number, they were punished with bitter-tasting quinine（奎宁）.

Once the bees had learned to consistently make the correct choice, the researchers gave them a new option: a white background containing no shapes at all. Even though the bees had never seen an empty picture before, 64% of the time they chose this option rather than a picture containing two or three shapes. This suggests that the insects understood that “zero” is less than two or three. And they weren’t just going for the empty picture because it was new and interesting: Another group of bees trained to always choose the larger number tended to pick the nonzero image in this test.

In further experiments, the researchers showed that bees’ understanding of zero was even more complex: For example, they were able to distinguish between one and zero-a challenge even for some other members of the zero club. Advanced number abilities like this could give animals an evolutionary（进化的）advantage, helping them find food sources. And if an insect can display such a thorough grasp of the number zero, then this ability may be more common in the animal kingdom than we think.

1.Why did the researchers do the experiments on bees?

A. To test bees’ abilities of understanding the concept of zero.

B. To see the different abilities between bees and other insects.

C. To help bees join the club of distinguishing smaller numbers.

D. To train the bees to help people collect much more honey.

2.What did trained bees probably choose in the experiment?

A. A picture with black shapes.    B. A picture with no shapes.

C. A picture with black background.    D. A picture with white shapes.

3.What can we infer from the last paragraph?

A. Bees are cleverer than other animals

B. Researchers find secrets in animals.

C. Animals have grasped the secret of zero.

D. Advanced number abilities may help animals survive.

4.What can be a suitable tile for the text?

A. Bees master the number skills

B. Bees join the club of smart animals

C. Bees understand the concept of zero

D. Bees have complex distinguishing system