4 now that： 既然，由于
Now that you have come you may as well stay. 既然你來了還是待著吧。
Now that oil is scarce， the fate of the motorcar is uncertain.
由于石油短缺，汽車將來的命運如何就難以預料了。
to leave …alone： 不管，不理；聽其自然
Leave me alone - take your hand off my arm. 別動我 - 松開我的胳膊。
I should leave that question alone if I were you. 如果我是你的話，我不會去碰這個問題。
out of step： 步伐不一致，不協(xié)調(diào)
That boy was out of step during most of the parade.
在*檢閱的大部分時間里，那個男孩的步伐都與別人的不合拍。
I‘m not good at dancing - I always get hopelessly out of step.
我不善長跳舞-總是踩不上點，已經(jīng)無可救藥了。
He is out of step with modern life. 他同現(xiàn)代生活不合拍。
課文精講：
Jet Lag： Prevention and Cure
The problem of Jet Lag is one every international traveler comes across at some time.⑴ But do you have to suffer？ Understand what it is， and how a careful diet can minimize its worst effects， and your flights will be less stressful. ⑵
1.此句中 “one” 代替前面出現(xiàn)過的 “problem” ， every international traveler comes across at some time 是定語從句修飾one， 省略了關(guān)系詞that 或which. to come across 意思是 “遇到，碰到”
全句意思：噴氣飛機時差綜合癥是每個乘坐國際航班旅行的人在某個時候會碰到的問題。
2.Understand what it is…這是個祈使句，相當于一個條件狀語從句：If you understand what it is…
例句：Work hard and you‘ll succeed. 相當于 If you work hard， you’ll succeed.
The effects of rapid travel on the body are actually far more disturbing than we realize.⑶Jet Lag is not a psychological consequence of having to readjust to a different time zone. It is due to changes in the body‘s physiological regulatory mechanisms， specifically the hormonal systems， in a different environment.
3.此句是個比較結(jié)構(gòu)。disturbing 是分詞式的形容詞，比較級是more disturbing，far 用來修飾比較級。
此句意思：乘飛機旅行對身體的影響實際上遠比我們意識到的更令人焦灼不安。
Confused？ So was John Foster Dulles， the American Secretary of State， when he flew to Egypt to conduct negotiations on the Aswan Dam ⑷He later blamed his poor judgment on Jet Lag.
4.此句中confused 的完整表達是 “Are you confused？” 后一句用了倒裝語序，so 位于句首，表示前面所說的情況也適合于本句。Blame…on…把過失歸咎于
此句意思：是不是被弄糊涂啦？美國國務(wù)卿約翰·福斯特·杜勒斯從美國飛往埃及談判阿斯旺水壩問題時就被弄糊涂了。他后來把自己在談判中判斷失誤歸咎于時差綜合癥。
The effects can be used to advantage， too. President Johnson once conducted an important meeting in Guam and kept the entire proceedings at Washington DC time. The White House working personnel were as fresh as paint， while the locals， in this case， were jet-lagged.⑸Essentially， they had been instantaneously transported to America.
5.該句是由 while 連接的兩個并列句，表示前后對比。in this case 作狀語，譯為“在這種情況下，” the locals 是指關(guān)島的本地人，作主語。
Now that we understand what Jet Lag is， we can go some way to overcoming it.⑹ A great number of the body‘s events are scheduled to occur at a certain time of day. Naturally these have to be regulated， and there are two regulatory systems which interact.
6.now that we understand what Jet Lag is， 原因狀語從句中有一個what引導的賓語從句，意為“既然我們了解了時差綜合癥是什么”。
One timing system comes from the evidence of our senses and stomachs， and the periodicity we experience when living in a particular time zone.⑺ The other belongs in our internal clocks （the major one of which may be physically located in a part of the brain called the suprachiasmatic nucleus） which， left alone， would tie the body to a 25 hour - yes， 25 - rhythm.⑻ Normally the two timers are in step， and the external cues tend to regularise the internal clocks to the more convenient 24 hour period.
7.該句主干結(jié)構(gòu)是“one timing system comes from…?！?； from 有兩個賓語，由and 連接。
此句意思：一個定時系統(tǒng)來自我們的感官和胃腸饑餓感以及我們在某個特定時區(qū)所經(jīng)受的周期性變化
8.該句的主干結(jié)構(gòu)“The other belongs in our internal clocks …”，which 引導定語從句修飾our internal clocks.在定語從句中，left alone 是過去分詞詞組作條件狀語，相當于條件狀語從句If it is left alone.括號中的定語從句也修飾our internal clocks.
此句意思：另一個定時系統(tǒng)在我們的體內(nèi)時鐘內(nèi)（其中一個主要時鐘可能位于我們大腦的稱為超交叉核的那部分中）這些體內(nèi)時鐘在不受干擾時，會使人體有一個25小時——是的，25小時——的生理節(jié)奏。
If， however， you move the whole body to a time zone which is four hours different， the two clocks will be out of step， like two alarm clocks which are normally set together， but which have been reset a few hours apart. ⑼ Whereas the two clocks would normally sound their alarms together， now they ring at different times. （10）Similarly， the body can be set for evening while the sun is rising.
Now that you have come you may as well stay. 既然你來了還是待著吧。
Now that oil is scarce， the fate of the motorcar is uncertain.
由于石油短缺，汽車將來的命運如何就難以預料了。
to leave …alone： 不管，不理；聽其自然
Leave me alone - take your hand off my arm. 別動我 - 松開我的胳膊。
I should leave that question alone if I were you. 如果我是你的話，我不會去碰這個問題。
out of step： 步伐不一致，不協(xié)調(diào)
That boy was out of step during most of the parade.
在*檢閱的大部分時間里，那個男孩的步伐都與別人的不合拍。
I‘m not good at dancing - I always get hopelessly out of step.
我不善長跳舞-總是踩不上點，已經(jīng)無可救藥了。
He is out of step with modern life. 他同現(xiàn)代生活不合拍。
課文精講：
Jet Lag： Prevention and Cure
The problem of Jet Lag is one every international traveler comes across at some time.⑴ But do you have to suffer？ Understand what it is， and how a careful diet can minimize its worst effects， and your flights will be less stressful. ⑵
1.此句中 “one” 代替前面出現(xiàn)過的 “problem” ， every international traveler comes across at some time 是定語從句修飾one， 省略了關(guān)系詞that 或which. to come across 意思是 “遇到，碰到”
全句意思：噴氣飛機時差綜合癥是每個乘坐國際航班旅行的人在某個時候會碰到的問題。
2.Understand what it is…這是個祈使句，相當于一個條件狀語從句：If you understand what it is…
例句：Work hard and you‘ll succeed. 相當于 If you work hard， you’ll succeed.
The effects of rapid travel on the body are actually far more disturbing than we realize.⑶Jet Lag is not a psychological consequence of having to readjust to a different time zone. It is due to changes in the body‘s physiological regulatory mechanisms， specifically the hormonal systems， in a different environment.
3.此句是個比較結(jié)構(gòu)。disturbing 是分詞式的形容詞，比較級是more disturbing，far 用來修飾比較級。
此句意思：乘飛機旅行對身體的影響實際上遠比我們意識到的更令人焦灼不安。
Confused？ So was John Foster Dulles， the American Secretary of State， when he flew to Egypt to conduct negotiations on the Aswan Dam ⑷He later blamed his poor judgment on Jet Lag.
4.此句中confused 的完整表達是 “Are you confused？” 后一句用了倒裝語序，so 位于句首，表示前面所說的情況也適合于本句。Blame…on…把過失歸咎于
此句意思：是不是被弄糊涂啦？美國國務(wù)卿約翰·福斯特·杜勒斯從美國飛往埃及談判阿斯旺水壩問題時就被弄糊涂了。他后來把自己在談判中判斷失誤歸咎于時差綜合癥。
The effects can be used to advantage， too. President Johnson once conducted an important meeting in Guam and kept the entire proceedings at Washington DC time. The White House working personnel were as fresh as paint， while the locals， in this case， were jet-lagged.⑸Essentially， they had been instantaneously transported to America.
5.該句是由 while 連接的兩個并列句，表示前后對比。in this case 作狀語，譯為“在這種情況下，” the locals 是指關(guān)島的本地人，作主語。
Now that we understand what Jet Lag is， we can go some way to overcoming it.⑹ A great number of the body‘s events are scheduled to occur at a certain time of day. Naturally these have to be regulated， and there are two regulatory systems which interact.
6.now that we understand what Jet Lag is， 原因狀語從句中有一個what引導的賓語從句，意為“既然我們了解了時差綜合癥是什么”。
One timing system comes from the evidence of our senses and stomachs， and the periodicity we experience when living in a particular time zone.⑺ The other belongs in our internal clocks （the major one of which may be physically located in a part of the brain called the suprachiasmatic nucleus） which， left alone， would tie the body to a 25 hour - yes， 25 - rhythm.⑻ Normally the two timers are in step， and the external cues tend to regularise the internal clocks to the more convenient 24 hour period.
7.該句主干結(jié)構(gòu)是“one timing system comes from…?！?； from 有兩個賓語，由and 連接。
此句意思：一個定時系統(tǒng)來自我們的感官和胃腸饑餓感以及我們在某個特定時區(qū)所經(jīng)受的周期性變化
8.該句的主干結(jié)構(gòu)“The other belongs in our internal clocks …”，which 引導定語從句修飾our internal clocks.在定語從句中，left alone 是過去分詞詞組作條件狀語，相當于條件狀語從句If it is left alone.括號中的定語從句也修飾our internal clocks.
此句意思：另一個定時系統(tǒng)在我們的體內(nèi)時鐘內(nèi)（其中一個主要時鐘可能位于我們大腦的稱為超交叉核的那部分中）這些體內(nèi)時鐘在不受干擾時，會使人體有一個25小時——是的，25小時——的生理節(jié)奏。
If， however， you move the whole body to a time zone which is four hours different， the two clocks will be out of step， like two alarm clocks which are normally set together， but which have been reset a few hours apart. ⑼ Whereas the two clocks would normally sound their alarms together， now they ring at different times. （10）Similarly， the body can be set for evening while the sun is rising.