When out of sight of land, a ship’s position can be found by

C

GUATEMALA CITY （Reuters） – A fish that lives in mangrove swamps（红树沼泽）across the Americas can live out of water for months at a time, similar to how animals adapted（适应）to land millions of years ago, a new study shows.

The Magrove Rivulus, a type of small killifish, lives in small pools of water in a certain type of empty nut or even old beer cans in the mangrove swamps of Belize, the United States and Brazil. When their living place dries up, they live on the land in logs（圆木），said Scott Taylor, a researcher at the Brevard Endangered Lands Program in Florida.

The fish, whose scientific name is Rivulus marmoratus, can grow as large as three inches. They group together in logs and breathe air through their skin until they can find water again.

The new scientific discovery came after a trip to Belize.

“We kicked over a log and the fish just came crowding out,” Taylor told Reuters in neighboring Guatgemala by telephone. He said he will make his study on the fish known to the public in an American magazine early next year.

In lab tests, Taylor said he found the fish can live up to 66 days out of water without eating.

Some other fish can live out of water for a short period of time. The walking catfish found in Southeast Asia can stay on land for hours at time, while lungfish found in Australia, Africa and South America can live out of water, but only in an inactive state. But no other known fish can be out of water as long as the Mangrove Rivulus and remain active, according to Patricia Wright, a biologist at Canada’s University of Guelph.

Further studies of the fish may tell how animals changed over time.

“These animals live in conditions similar to those that existed millions of years ago, when animals began making the transition（过渡）from water onto land,” Wright said.

49. The Mangrove Rivulus is a type of fish that _______.

A. likes eating nuts

B. prefers living in dry places

C. is the longest living fish on earth

D. can stay alive for two months out of water

When a buoy is in position only during a certain period of the year，where may the dates when the buoy is in position be found?

A.Light List

B.Notice to Mariners

C.On the chart

D.Coast Pilot

A、No, I can’t.

B、It’s none of my business.

C、I’ve got no idea

D、Yes, I can.

A fairly accurate estimation of a ship’s position can be calculated by a technique know as ___.

A.dead reckoning

B.pilotage

C.great circle sailing

D.geographic navigation

The term of Landfall means ________ ．

A.Land first sighted when vessel approaching from seaward

B.Land last sighted when vessel leaving from a port

C.in sight of one another when vessel underway

D.in sight of an island during a ship on her voyage

______is the process by which the position of the vessel at any moment is found by applying the last well-determined position to the run that has been made since, using for this purpose the ship’s course and the distance being those indicated by log.

A.dead reckoning

B.dead weight

C.dead slow ahead

D.dead slow astern

When does a pilot say “ Make all lines fast”? ________

A.The ship is about to be in position

B.The ship is very close to the berth

C.The ship is on voyage

D.The ship is in position