Within a few years oceanography was under way. In 1872 Thomson led a scientific expedition (考察), which lasted for four years and brought home thousands of samples from the sea. Their classification and analysis occupied scientists for years and led to a five-volume report, the last volume being published in 1895.

　　注：oceanography 最末一段與第一段首句都出現 oceanagraphy, 回環結構。

　　21. The passage implies that the telegraph cable was built mainly _________.

　　A) for oceanographic studies

　　B) for military purposes

　　C) for business considerations

　　D) for investigating the depths of the oceans

　　注：推理題。定位第三段,倒數第三行。選項 D 的內容出現在第四段，為竄段選項

　　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.

　　22. It was ________ that asked Maury for help in oceanographic studies.

　　A) the American Navy

　　B) some early intercontinental travellers

　　C) those who earned a living from the sea

　　D) the company which proposed to lay an undersea cable

　　注：細節題。定位第四段,選項 B和C是竄段選項

　　It was to Maury of the US Navy that the Atlantic Telegraph Company turned, in 1853, for information on this matter. In the 1840s, Maury had been responsible for encouraging voyages during which soundings (測深) were taken to investigate the depths of the North Atlantic and Pacific Oceans. Later, some of his findings aroused much popular interest in his book The Physical Geography of the Sea.

　　23. The aim of voyages Maury encouraged in the 1840s was __________.

　　A) to make some sound experiments in the oceans

　　B) to collect samples of sea plants and animals

　　C) to estimate the length of cable that was to be made

　　D) to measure the depths of two oceans

　　注：1.細節題。定位第四段，第二行。