计算机无法推断出1个月以后的某一天，新泽西州的普林斯顿究竟是晴天还是雨天。正午时分，传感器之间的距离会掩盖计算机无法知道的波动、任何偏离平均值的变化。到12∶01时，那些波动就已经会在1英尺远的地方造成偏差。很快这种偏差会增加到10 英尺的范围，如此等等，一直到全球的范围。

Comprehension  理解

Give short answers to these questions in your own words as far as possible．Use one complete sentence for each answer.

1  What does the author mean by‘small pieces of weather’?

2  How do modern weather models work ?

3  What do you think‘the butterfly effect’means in this passage?

Vocabulary  词汇

Refer to the text to see how the following words have been used, then write sentences of your own using these words: speculative (1.1); global (1.3); deteriorates (1.4); rapidly (1.4); multiply (1.4); turbulent (1.5); suppose (1.10); accurate (1.10); precisely (1.11); data (1.12); fluctuations (1.14); average (1.15); errors (1.16).

The paragraph  段落

A  Which one of these statements do you think the author would agree with?

1  Accurate readings by computers enable us to predict the weather.

2  It will never be possible to predict the weather accurately.

3  The only way to predict the weather accurately is to have sensors one foot apart, rising at one-foot intervals all the way to the top of the atmosphere.

Key structures  关键句型

A  Note how these two sentences have been connected:

Errors and uncertainties multiply．They cascade upward through a chain of turbulent features.

Errors and uncertainties multiply, cascading upward through a chain of turbulent features．(11.4-5)

Join these sentences in the same way:

1  There's a fault in the earth's crust．It runs along the west coast of the USA.

2  The hurricane hit Florida．It swept away everything in its path.

3  I noticed the lights were on．I assumed they were at home.

4  He emerged from the airport．The president waved to the reporters.

B  We can introduce conditional sentences with conjunctions other than if, for example:

Suppose the earth could be covered with sensors spaced one foot apart．(11.8-9)

Complete these sentences in any way you like:

1  You can go home early, providing (that) ______.

2  We can offer you a job on condition (that) ______.

3  You can come in any time you like tomorrow morning so long as ______.

4  I won't phone you unless ______.

5  He'll definitely win even if ________.

C  Study these two sentences:

We will probably have some rain by noon.

By 12.01  those fluctuations will already have created small errors one foot away．(11.15-16)

Explain the differences in meaning between these pairs of sentences:

1  He won't receive this fax tomorrow morning.

He will have received this fax by tomorrow morning.