In the third paragraph, the word “striking means . A. unusual B. simple C. weak D——青夏教育精英家教网—

In the third paragraph, the word “striking means . A. unusual B. simple C. weak D. slow (9) Some spiders hunt on the ground, others build webs to trap their food, but the grass water spider catches its prey by running along the surface of the water. This special water spider lives on the grassy banks of streams where mosquitoes, damsel flies and other insects come to feed and breed. Although it is one of the largest spiders in New Zealand, it has an unusual ability. It doesn’t disturb the water as it waits for its meal, and there is barely a ripple when it skims across the surface at lightning speed to catch its prey. Grass water spiders deal swiftly with larger insects like damsel flies by pulling their heads under the water and holding them there until they drown. After a meal, the grass water spider spends up to half an hour grooming itself. It wipes its eight eyes, brushes its antennae, and takes special care to clean the hairs on its body. It is the hairs that trap tiny bubbles of air so that the spider can run down a blade of grass and stay underwater for up to an hour when it is frightened. The hairs also keep the spider dry, even underwater. It is only when the female spider is caring for the young that she does not hunt on the water. After mating, she produces a large egg sac(囊), which she carries around for five weeks. Once the eggs start to hatch, she attaches the sac to some blades of grass or a thistle. She then tears the sac open and releases the tiny spiders into the nursery web. 【查看更多】

Space travel is definitely bad for astronauts’ bones, reducing their bone density(密度) after only a month of weightlessness, according to French research published on Friday.

Laurence Vico and his fellow workers at St Etienne University called for more research into the effects of microgravity, after their study of 15 astronauts from the Russian MIR station showed bone loss continued throughout space flights.

“Bone loss was especially striking in four astronauts, ” the scientists reported in the Lancet Medical Journal.

They measured the bone mineral density (BMD) of bones in the forearm(前臂) and lower leg of the astronauts who had spent one to six months in space.

The BMD loss was significant in the tibia(胫骨) of the lower leg, a weight-bearing bone, but barely changed in the radius(桡骨) of the forearm. “Our results indicate the need to investigate not only different bones, but also different areas of the same bone since not all sites of the skeleton (骨架) are similarly affected by space conditions, ” they added.

Without gravity the body isn’t bearing any weight so there is no need for calcium (钙) which makes bones strong, and it becomes empty into the bloodstream.

The research team suggested in future scientists should try to determine if the loss of bone density was only on weight-bearing bones on longer flights, also the possible recovery after returning to Earth.

French scientists did their research on Russian astronauts, because _______.

A. they only cared for the Russian astronauts

B. they were not interested in their own astronauts

C. the Russian government invited them to do their research

D. the Russian astronauts worked in space for a long time

Scientists have found that _______.

A. the BMD loss may cause serious illness to astronauts

B. the BMD loss may cause some change in astronauts’ bodies

C. astronauts shouldn’t care about the BMD loss

D. astronauts should take some calcium before space travel

What cause the BMD loss to astronauts, according to this passage?

A. The food they eat in space. B. The drinks they take in space.

C. The temperature in space. D. The gravity in space.

In the third paragraph, the word “striking” means ______.

A. unusual B. simple C. weak D. slow

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