高一英語必修三-unit-4課文詳解-展示頁
2024-08-31 00:17本頁面
【正文】 denly disappeared still remains a mystery. 他們?yōu)槭裁磿蝗粶缃^至今仍是個謎。 laid eggs too and existed on the earth for more than 140 million years. 他們也生蛋，在地球上生存了一億四千多萬年。 produced young entirely by laying eggs. 他們一般是通過孵蛋而繁衍后代的。 were insects. Others, called amphibians, were able to live on land as well as in the water. 隨后，陸地上出現(xiàn)了動物，其中有一些是昆蟲，另外一些叫兩棲動物，他們既能在陸上生活，也能在水里生存。 multiplied and filled the oceans and seas with oxygen, which encouraged the later development of early shellfish and all sorts of fish. 他們繁殖起來就使得海洋充滿了氧氣，這為早期的貝類及其他各種魚類后來的進化創(chuàng)造了條件。 produced a chain reaction, which made it possible for life to develop. 這就產(chǎn)生了一系列的反應(yīng)，使得生命就有可能開始發(fā)展了。 was not immediately obvious that water was to be fundamental to the development of life. 水對于生命的發(fā)展會起關(guān)鍵作用，這一點在當(dāng)時并不明顯。 5. What is even more important is that as the earth cooled down, water began to appear on its surface. 更為重要的是，地球冷卻了下來，地球的表面就開始出現(xiàn)了水。 Par 2 exploded loudly with fire and rock. They were in time to produce carbon, nitrogen, water vapour and other gases, which were to make the earth39。 it was to bee was uncertain until between and billion years ago when the dust settled into a solid globe. 隨后它會變成什么沒人能知道，直到 38— 45億年前，這團塵埃才慢慢地形成一個固體的球狀物。 that, atoms began to form and bine to create stars and other bodies. 然后，原子開始形成并結(jié)合成恒星和其他天體。HOW LIFE BEGAN ON THE EARTH 地球上生命的起源 UNIT 4 課文講解 one knows exactly how the earth began, as it happened so long ago. 沒有人確切知道地球是怎樣開始形成的，因為在很早很早以前地球就形成了。 , according to a widely accepted theory, the universe began with a Big Bang that threw matter in all directions. 然而，一種普遍為人們所接受的理論是：宇宙起源于一次大爆炸，這次大爆炸將物質(zhì)投射到四面八方。 Par 1 several billion years after the Big Bang, the earth was still just a cloud of dust. 大爆炸后好幾十億年過去了，但地球還只是一團塵埃。 earth became so violent that it was not clear whether the shape would last or not. 地球（開始）變得激烈動蕩，不知道這個固體形狀是否會繼續(xù)存在下去。s atmosphere. 它（地球）猛烈地爆炸噴出了烈火與巖石，最終產(chǎn)生了碳，氮氣，水蒸氣和其他多種氣體，從而形成了地球的大氣層。 1. Water had also appeared on other plas like Ma
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