Questions 21 to 25 are based on the following passage:

　　Oceanography has been defined as 'The application of all sciences to the study of the sea'.

　　注：

　　1.Oceanography 由 Ocean (海洋) 和 graphy (學科)組成，意為“海洋學”

　　2.application 表示“申請”用介詞for,表示“應用”用介詞to

　　3.第一句給某個東西下定義，稱為篇章定義，必為文章主題

　　Before the nineteenth century, scientists with an interest in the sea were few and far between. Certainly Newton considered some theoretical aspects of it in his writings, but he was reluctant (不愿意) to go to sea to further his work.

　　注：

　　1.第二段：在十九世紀之前，對海洋感興趣的科學家很少，可以推斷本文根據時間順序來描述海洋學發展的過程

　　2.further 跟在 to 后面是個動詞，表示“推進”

　　For most people the sea was remote, and with the exception of early intercontinental travelers or others who earned a living from the sea, there was little reason to ask many questions about it, let alone to ask what lay beneath the surface. The first time that the question 'What is at the bottom of the oceans?' had to be answered with any commercial consequence was when the laying of a telegraph cable from Europe to America was proposed. The engineers had to know the depth profile (起伏形狀) of the route to estimate the length of cable that had to be manufactured.

　　注：

　　1. remote 遙遠的

　　2. and with...多重復合句

　　3. intercontinental 洲際的 (Inter 在之間，continent 大洲)

　　4. let alone 更不用說……

　　5. first time 由不感興趣轉折到感興趣 ，謂語是 was

　　6. 第二句that引導同位語從句，when引導表語從句，整句意思為“當有人基于商業目的建議在美國和歐洲之間鋪設電報電纜的時候，人們才提出問題：海底是什么?”

　　7.route 路線 router 路由器