15．A hole at the bottom of a ship will allow water to flood into the hull（船體），causing it to sink．But believe it or not，most large ships sailing over the deep ocean waters actually have one or more good-sized holes at their bottom!These holes have been given a rather fanciful name-moon pool．A moon pool is basically an opening located at the floor or the hull of a sailing ship，which is used for gaining easier and safer access to the water below．
Above Sea Level
This is the first and most basic type of the moon pool．It is located within a sailing ship，inside a chamber（船艙） that is built above sea level．This chamber is constructed such that it is easily accessible via hallways and stairways，inside the sailing shup．This type usually requires ships to have a twin-hull design，and is most commonly found on oil drilling platforms．
At Sea Level
This type is found in ships with a single hull design．In these ships，the hull is well below sea level，which causes the water to rise up inside the opening of the moon pool，making it seem there is a swimming pool．To prevent the rising water from flooding the hull and sinking the ship，the sides of the moon pool are designed such that they rise up higher than water level in the pool，containing an overflow（溢流管）．This type also has doors present inside the hull．The openings to the moon pool can be closed by shutting the doors．
Below Sea Level
This type of moon pool is present below sea level．The chamber housing the moon pool is made completely airtight（不透氣的） with a two-door mechanism．The first door opens to the hull while the second one opens to the sea water．When a diver wants to enter the water，he will enter into the middle chamber through the first door，while the second one is kept locked．Once the dive is inside the chamber，the first door is locked．Then the second door is opened and the diver is able to enter the water．To get back in，he will need to get into the chamber through the second door while the first remains locked．Once he is inside the chamber，the second door is closed，and the water in the chamber is pumped out before the first door is opened． In Submerged Habitats（水下居住艙）
This type is usually found in deep underwater habitats，which are made completely airtight and filled with air up to normal atmospheric pressure．The moon pool provides the only way to enter or exit from these habitats．The entry and exit mechanism is similar to the one used by the below sea level type of moon pools．
59．A moon pool on an oil drilling platformC．
A．has doors present inside the platform
B．looks like a swimming pool in the platform
C．is easy to access through hallways and stairways
D．has higher sides than water level in the pool
60．Moon pools in ships with a single hull design are often builtB．
A．above sea level B．at sea level C．below sea level D．in submerged habitats
61．What is the right procedure for getting back in the hull through the moon pool below sea level？D
a．Open the first door．b．Pump the water put．
c．Close the second door．d．Enter the secong door．
A．d，b，c，a B．d，a，b，c C．a，b，d，c D．d，c，b，a．
分析 本文主要講述了各種大型船體上設計的各種moon pool．
解答 59．C細節(jié)理解題．根據(jù)文章第二段第三句"This chamber is constructed such that it is easily accessible via hallways and stairways，inside the sailing shup．"可知石油鉆井平臺上的 moon pool可以很容易通過走廊和樓梯訪問．故選C．
60．B細節(jié)理解題．根據(jù)文章第三段可知在單一的船體上moon pool設計在海平面以上，防止水位上升淹沒下沉的船體．故選B．
61．D細節(jié)理解題．根據(jù)第四段可知海平面以下的船體設計是有兩個moon pool，通過moon pool要回到船體必須要先進入第二門然后關閉第二道門其次要水泵放水打開第一道門．故選D．
點評 本文是廣告布告類閱讀理解．做這類題材閱讀理解時要求考生對文章通讀一遍，做題時結合原文和題目有針對性的找出相關語句進行仔細分析，結合選項選出正確答案．推理判斷題也是要在抓住關鍵句子的基礎上合理的分析才能得出正確答案，切忌胡亂猜測，一定要做到有理有據(jù)
