B

　　Robotic surgery is one thing, but sending a robot inside the body to carry out an operation is quite another, which has long been a goal of some researchers to produce tiny robotic devices being capable of traveling through the body to deliver drugs or to make repairs without the need for a single cut, the possibility of which has just got a bit closer.

　　However, unlike the plot of one film-which featured a microscopic (微小的)crew and submarine(潜艇) traveling through a scientist's bloodstream - this device could not be inserted into blood vessels（管）because it is too big. While other types of miniature(微型的) swallowable robots have been developed in the past, their role has mostly been limited to capturing images inside the body. In a presentation this week to the International Conference, Daniela Rus and Shuhei Miyashita of the Massachusetts Institute of Technology described a robot they have developed that can be swallowed and used to collect dangerous objects accidentally taken in.

　　To test their latest version, Dr Rus and Dr Miyashita designed a robot as a battery hunter, which might seem to be an odd(奇怪的) task, but more than 3,500 people in America alone, most of them children, swallow the tiny button cells used in small electronic devices by accident every year. To start with, the researchers created an artificial esophagus（食道）and stomach made out of silicone(硅胶). It was closely modeled on that found in a pig and filled with medical liquid; the robot itself is made from several layers of different materials, including pig intestine（肠）, and contains a little magnet(磁铁). This is folded up and encased in a 10mm×27mm capsule of ice. Once this reaches the stomach the ice melts and the robot unfolds which is moved and guided with the use of a magnetic field outside the body. In their tests, the robot was able to touch a button battery and draw it with its own magnet, and during dragging it along, the robot could then be directed towards the intestines where it would eventually be gotten rid of through the anus(肛门). After it, the researchers sent in another robot loaded with medication to deliver it to the site of the battery burn to speed up healing.

　　The artificial stomach being transparent on one side, the researchers were able to see the batteries and visually control the robots. If not, that will require help with the help from imaging system, which will be a bit more of a challenge, but Dr Rus and Dr Miyashita are determined to succeed.

58. We learn from Paragraph 3 that _________.

　A. the researchers did the experiment on a chosen animal

　B. the robot took necessary drugs besides a little magnet

　C. the actual size of the robot may be larger than the capsule of ice

　D. digesting the swallowed batteries is difficult for children

59. What may the experiment mean to the medical world?

　A. The surgeries will cost patients much money.

　B.Fewer children will swallow the button cells.

　C.A robot will be invented travelling blood vessels.

　D. Patients will suffer less for some surgeries.

60. Which can be the most suitable title for the passage?

　A. An Experiment on Robot B. The Fantastic Robotic Voyage

　C. Tiny Robot, Significant Role D. The Exploration of Robot Technology

　C

　　 Conventional wisdom says that hardship can make us before our time. In fact, a new study suggests that violence not only leaves long-term scars on children's bodies, but also changes their DNA, causing changes that equal to seven to ten years of premature aging (提前衰老).

　　"Scientists measured this by studying the ends of children' s chromosomes(染色体), called telomeres." says Idan Shalev, lead author of a study published in Molecular Psychiatry.

Telomeres are special DNA sequences (序列)which prevent the DNA in chromosomes from separating. They get shorter each time a cell divides, until a cell cannot divide any more and dies.