Hundreds of feet below the ocean's surface，somewhere between the dark ocean floor and the bright blue shallows，lies the twilight zone.It's a world of the unknown，and many assumed that the lack of light and cold temperatures meant few species could exist there.
But one scientist has been diving into the inky depths to show there's much more to life there than was first thought.Rocha，a researcher from the California Academy of Sciences，was attracted to twilight zone reefs because of their mystery （神秘）. "Every dive we do to those depths leads to a new discovery，" he says.To date，he has identified over 300 new species.
Entering the twilight zone is no easy feat.Recreational diving is capped at 130 feet for safety reasons，but Rocha dives as far as 500 feet.To do this requires deep concentration，intense technical training and a strong dose of bravery.Rocha usually dives in a group with two scientists and one safety officer.They spend hours preparing the kit，ensuring every piece of equipment is functioning well and that they are equipped to deal with underwater emergencies.
While the twilight zone has been explored by very few people，the effects of human activity are still apparent.One of their first discoveries is that those deeper reefs are really not a shelter for shallow reef organisms.They are almost as impacted as the shallow reefs are.They find plastic waste and fishing gear in some of the deepest reefs and has observed the impact of overfishing and climate change.
Rocha hopes that his research can help to educate people about the twilight zone and inspire action to protect it. "I don't think it's enough just to do the science.We take many，many photographs…and we bring those stories back up to the surface and we share it with as many people as possible.For the most part，I'd like to let people realize that those creatures are under threat，" he says.
（1）Why do many people think there is few species at the twilight zone？
B
B
A．It isn't far from the ocean's surface.
B．It is cold and lacks light.
C．It is completely dark all day.
D．It is a world that people cannot get to.
（2）What can we know about the twilight zone？
C
C
A．There are only a lot of reefs there.
B．People have much knowledge about it.
C．There are a large number of various living things.
D．There aren't as many species as people think before.
（3）How is Rocha's journey to the twilight zone？
A
A
A．It is risky.
B．It is easy.
C．It is comfortable.
D．It is lonely.
（4）What can be inferred from Rocha's words in the last paragraph？
C
C
A．His scientific research is hardly inspirational.
B．Taking pictures underwater is enjoyable.
C．Humans are responsible for protecting the twilight zone.
D．The research at the twilight zone is now under threat.
