3. Scientist (感到不解) as to why the whale had swum to the shore.

2. What happened to the ship (仍然是個跡) .

根據(jù)括號內(nèi)的漢語提示補全下面句子。

1. (令我不解的) was why he left the country without telling anyone.

[語境展不]閱讀下面句子，并試著歸納puzzle的意思及用法。

1. My sister likes doing crossword puzzles.

2. Scientists have been trying to solve this puzzle for years.

3. The findings of the survey puzzle me — they’ re not at all what I could have expected.

4. Susan' s been puzzling about / over this strange letter for weeks.

[自我歸納]puzzle既可作名詞,也可作動詞。

★作名詞時，意為:①謎，智力游戲(句1) ;②難題，謎般的事物(句2) 

★作動詞時，意為 “”,常用于以下結(jié)構(gòu):puzzle sb.使某人困惑

(句3) ; puzzle about / over sth.苦苦思索，仔細(xì)琢磨(句4) 。

2. What is even more important is that as the earth cooled down,water began to appear on its surface?

(P26)

[分析]

① 本句是一個主從復(fù)合句。

② 主句是What is even more important is,that 引 導(dǎo)從句。

③ 主句中包含二個由what引導(dǎo)的主語從句，that從句中

包含一個由 引導(dǎo)的時間狀語從句。

[句意]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。

[仿寫]更為奇怪的是，我下公交車時，又看見了那位老 太太。

1. What it yas to become was uncertain until between 4. 5 and 3. 8 billion years ago when the dust settled into a solid globe. (P25)

[分析]

① 本句是一個主從復(fù)合句。

② 主句是 What it was to become was uncertain until between 4. 5 and 3. 8 billion years ago,when 引導(dǎo) 從句。

③ 主句中包含一個由what引導(dǎo)的主語從句，what在從句中作 。

[句意]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。

[仿寫]杰克打算做什么我不知道，直到第二天早上，他 才告訴了我他的計劃。

Task IV. Read the text and decide whether the following statements are True (T) or False (F) .

1. The earth was in the shape of a cloud of dust after the “Big Bang”.

2. Carbon dioxide,nitrogen,water vapour and other gases formed the earth' s atmosphere.

3. The harmful gases and acids came from the oceans.

4. Reptiles came into being before amphibians.

5. Mammals gave birth to young babies and produced milk for them.

6. Life on the earth has much to do with how people look after it.

Task III. Read the text and combine the two halves of the sentences.

1. Atoms                        A. provided oxygen for the oceans and seas.

2. The earth explosion               B. combined and formed stars.

3. The water on Mars                 C. stops the heat escaping from the earth.

4. The extremely small plants           D. could live on land and in the water.

5. Amphibians                      E. produced carbon dioxide,nitrogen,water vapour and other gases.

6. Reptiles                        F. suddenly disappeared and no one knows the reason.

7. Dinosaurs                        G. disappeared later.

8. Carbon dioxide                     H. mostly lay eggs to produce younger generations.

Task II. Read Paragraph 4 and complete the following chart showing the development of the living things on the earth.

1.2.3.4.5.

Task I. Read the text and fill in the blanks in the chart below. Try to understand how life began and developed on the earth.

1.2.3.4.5.6.