Bootlace worms boast spooky-stretchy bodies. Their secret： They also secrete a family of toxins new to science. These poisons might one day inspire novel ways to control noxious pests， such as cockroaches.

Tests first identified the toxins in the mucus coating one bootlace species. It holds the record as the worlds longest animal， notes Ulf G?ransson. At Uppsala University in Sweden， he studies medical products that come from natural sources. This champion marine worm， Lineus longissimus， can stretch up to 50 meters. The worm coats itself in mucus that smells a bit like iron or sewage. This goo holds small toxic proteins that have now been dubbed nemertides. Those poisons also have shown up in 16 other species of bootlace worms.

G?ransson and his colleagues shared their discovery in Scientific Reports. These nemertides poison by attacking some of the tiny channels in cell walls. These channels control the flux — flow rate — of sodium moving in and out of a cell. Much vital cell business depends on the right flux through these sodium channels， as theyre called. Among that important business： cell-to-cell communication.

The researchers injected small amounts of one nemertide into invasive green crabs . The toxin permanently paralyzed or killed these animals.

Unlike earthworms， the 1 300 or so species of bootlace — or ribbon — worms have no segments. Some scientists give these animals their own branch， call Nemertea， on the animal family tree. Bootlace worms have a brain but no lungs. These worms breathe directly through the skin. One has to marvel at how they can expand and contract their bodies. “A 10-meter Lineus longissimus can be held in your hand as a slimy heap，” notes study coauthor Malin Strand. Shes a marine biologist. She estimates these worms could live 10 years or maybe much longer.How bootlace worms use their toxins isnt clear. The stringy creatures arent easy to keep in captivity for study， Strand says. She has some worms in her lab that have chosen to eat no more than once in three to four years.

G?ransson proposes that their toxic mucus might make a useful defense. He has seen videos with the worms stretched upon the seafloor. “If youre a crab， it must be tempting to take a nip，” he says. However， theres little sign of anything pestering these worms.He once tried some bare-handed contact with a small lab specimen. Hes been warned， though， about “tingling.” Just in case， he now wears gloves.

Answer the following questions

1. Which of the following is NOT suitable for the description of bootlace worms？

A） No other animal can beat them in length.

B） They dont have segments.

C） Their skin serves as respiratory organ.

D） They have a brain， a heart and two lungs.

2.What does “This goo” refer to in Paragraph 2？

A） the worm B） the mucus

C） the smell D） the sewage

3. What might happen if a ribbon worm stretches upon the seafloor？

A） It might be eaten by a fish.

B） It might become prey to a crab.

C） It can enjoy its peaceful time.

D） Other species may take a nip of it.

4. The research may shed light on ______.

A） the development of medicine

B） the evolution of marine species

C） the study of zoology

D） the study of civil engineering

New Tech Helps Deaf-blind People "Watch"TV

You may enjoy TV — as do many people with hearing or visual disabilities. But those who are both deaf and blind need special help to follow along. Now an innovative （A） t_______ is turning television signals into a form that deaf-blind people can understand.

?ngel García Crespo is a computer （1） e_______ at Carlos III University of Madrid in Spain. His group has invented a new system for deaf-blind people to “watch” （B） t_______.

Deaf-blind people rely on their sense of touch to communicate. One way to get （C） i_______ is to have someone on hand — literally. A deaf-blind person can get and give information through touch-based hand signals with another person. But it isnt always “handy” to have （2） s_______ else around.

Deaf-blind people can also get and send information with a braille line， better known as a refreshable braille display. The braille （D）s_______ uses patterns of raised dots to stand for letters and numbers. A refreshable braille display is an electronic （E）m_______ with a changeable braille display. Dots or pins rise up or drop down based on electronic information sent to the machine. With such a portable device， someone who cannot see a screen can still read email or other information from a computer.

The new system converts TV （3） s_______ to data that a refreshable braille display can use. Key to the system is the possibility of using subtitles to collect TV information. Subtitles travel with the image and the audio in electromagnetic waves that we do not see. But an electronic system can capture those waves. This is done in real time， in less than a （F） s_______. This lets a deaf-blind person “watch” TV as it is broadcast. The system will work with all types of refreshable braille displays， as long as there is a Bluetooth connection available.

That is what García Crespo and his group are doing.

Currently， the system is only used in Europe. Indeed， it should soon be （4） a_______ in the United States.

（A， B， C， D， E， F FOR CROSS， 1， 2， 3， 4 FOR DOWN. The first letters of the absents were given.）

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