Lesson 7 Bats

Not all sounds made by animals serve as language.

動物發出的聲音不都是用作語言交際。

Lesson 7 Bats

and we have only to turn to that extraordinary discovery of echo-location in bats to see a case in which the voice plays a strictly utilitarian role.

我們只要看一看蝙蝠回聲定位這一極不尋常的發現，就可以探究一下聲音在什么情況下有絕對的實用價值。

Lesson 7 Bats

To get a full appreciation of what this means we must turn first to some recent human inventions.

要透徹理解這句話的意義，我們應先回顧一下人類最近的幾項發明。

Lesson 7 Bats

Everyone knows that if he shouts in the vicinity of a wall or a mountainside, an echo will come back.

大家都知道，在墻壁或山腰附近發出的喊聲，就會聽到回聲。

Lesson 7 Bats

The further off this solid obstruction, the longer time will elapse for the return of the echo.

固體障礙物越遠。回聲返回所用時間就越長。

Lesson 7 Bats

A sound made by tapping on the hull of a ship will be reflected from the sea bottom,

敲打船體所發了的聲音會從海底傳回來，

Lesson 7 Bats

and by measuring the time interval between the taps and the receipt of the echoes, the depth of the sea at that point can be calculated.

測出回聲間隔的時間，便可算出該處海洋的深度。

Lesson 7 Bats

So was born the echo-sounding apparatus, now in general use in ships.

這樣就產生了目前各種船舶上普遍應用的回聲探測儀。

Lesson 7 Bats

Every solid object will reflect a sound, varying according to the size and nature of the object.

任何固體者反射聲音，反射的聲音因物體的大小和性質的不同而不同。

Lesson 7 Bats

A shoal of fish will do this.

魚群也反射聲音。

Lesson 7 Bats

So it is a comparatively simple step from locating the sea bottom to locating a shoal of fish.

從測定海深到測定魚群，這一進展比較容易。

Lesson 7 Bats

With experience, and with improved apparatus,

根據經驗和改進了的儀器，

Lesson 7 Bats

it is now possible not only to locate a shoal but to tell if it is herring, cod, or other well-known fish, by the pattern of its echo.

不僅能夠確定魚群的位置，而且可以根據魚群回聲的特點分辨出是鯡魚、鱈魚，這是人們所熟悉的其他魚。

Lesson 7 Bats

It has been found that certain bats emit squeaks and by receiving the echoes,

人們發現，某些蝙蝠能發出尖叫聲，

Lesson 7 Bats

they can locate and steer clear of obstacles -- or locate flying insects on which they feed.

并能通過回聲來確定并躲開障礙物，或找到它們賴以為生的昆蟲。

Lesson 7 Bats

This echo-location in bats is often compared with radar, the principle of which is similar.

蝙蝠這種回聲定位常常可與雷達相比較，其原理是相似的。

Lesson 8 Trading standards

Chickens slaughtered in the United States, claim officials in Brussels, are not fit to grace European tables.

布魯塞爾的官員說，在美國屠宰的雞不適于用來裝點歐洲的餐桌。

Lesson 8 Trading standards

No, say the American: our fowl are fine, we simply clean them in a different way.

不，美國人說，我們的家禽很好，只是我們使用了另一種清洗方式。

Lesson 8 Trading standards

These days, it is differences in national regulations, far more than tariffs, that put sand in the wheels of trade between rich countries.

當前，是各國管理條例上的差異，而不是關稅阻礙了發達國家之間的貿易。

Lesson 8 Trading standards

It is not just farmers who are complaining.

并不僅僅是農民在抱怨。

Lesson 8 Trading standards

An electric razor that meets the European Union's safety standards must be approved by American testers before it can be sold in the United States,

一把符合歐洲聯盟安全標準的電動剃須刀必須得到美國檢測人員的認可，方可在美國市場上銷售；

Lesson 8 Trading standards

and an American-made dialysis machine needs the EU's okay before is hits the market in Europe.

而美國制造的透析儀也要得到歐盟的首肯才能進入歐洲市場。

Lesson 8 Trading standards

As it happens, a razor that is safe in Europe is unlikely to electrocute Americans.

碰巧在歐洲使用安全的剃須刀不大可能使美國人觸電身亡，

Lesson 8 Trading standards

So, ask businesses on both sides of the Atlantic, why have two lots of tests where one would do?

因此，大西洋兩岸的企業都在問，當一套測試可以解決問題時，為什么需要兩套呢？

Lesson 8 Trading standards

Politicians agree, in principle,

政治家在原則上同意了， 因此，

Lesson 8 Trading standards

so America and the EU have been trying to reach a deal which would eliminate the need to double-test many products.

美國和歐洲一直在尋求達成協議，以便為許多產品取消雙重檢查。

Lesson 8 Trading standards

They hope to finish in time for a trade summit between America and the EU on May 28TH.

他們希望盡早達成協議，為5月28日舉行的美國和歐洲貿易的最高通級會議作準備。

Lesson 8 Trading standards

Although negotiators are optimistic, the details are complex enough that they may be hard-pressed to get a deal at all.

然談判代表持樂觀態度，但協議細節如此復雜，他們所面臨的困難很可能使他們無法取得一致。

Lesson 8 Trading standards

Why? One difficulty is to construct the agreements.

為什么呢？困難之一是起草這些協議。

Lesson 8 Trading standards

The Americans would happily reach one accord on standards for medical devices and them hammer out different pacts covering,say,

美國人很愿意就醫療器械的標準達成一個協議，然后推敲出不同的合同，用以涵蓋 --比如說