41. Osteoporosis refers to the ____________.
(A) bone loss
(B) slow growth
(C) weight problem
(D) blood pressure

1969 年 7 月，全世界目睹了兩名男子踏上月球。人類第一次冒險走出地球，觸及到超越世界的可能性。但自 1970 年代和 1980 年代以來，我們的太空旅行野心似乎停滯不前。 30 多年來，我們幾乎沒有比最初的先驅者更進一步。隨著越來越多的宇航員在各個空間站上花費更多時間，他們報告了令人擔憂的健康問題。

正如最近的悲慘事件所表明的那樣，任何太空旅行中最危險的部分就是起飛。試圖達到逃離地球引力所需的速度充滿了危險。但即使他們到達太空，宇航員也沒有脫離危險。相反，他們面臨著一系列我們才剛剛開始了解的新風險。

宇航員克里斯·哈德菲爾德在國際空間站的太空中生活了幾個月。根據哈德菲爾德的說法，零重力改變了他的身體，以及他在高速微隕石不斷威脅下的生活方式。

我們生來就生活在地球上，而不是生活在太空中的極端條件下。所以當像克里斯哈德菲爾德這樣的宇航員離開我們的星球時，他們必須帶著他們的環境。這就是為什麼他們穿著特別設計的太空服。但宇航服的作用遠不止將地球大氣層保持在宇航員周圍。多年來，宇航服設計不斷發展，以保護人類免受太空的嚴酷考驗。

在地球軌道上，宇航員可能會經歷低至 -129°C (-200°F) 和高達 121°C (250°F) 的溫度。太空服經過巧妙設計，可以保護我們免受這些極端條件的影響。它們還提供氣壓，以防止我們的體液在太空的嚴密真空中沸騰。但宇航員只能穿著今天存在的宇航服旅行這麼遠。即使是我們最好的套裝也僅限於“近地軌道”。為了進一步深入太陽系，我們需要一套新的防護服——它可以保護我們免受深空的致命危險。但即便如此，我們是否足夠強大，能夠在長期任務中生存下來？

太空服可能會在外部保護我們，但太空會對人體的內部運作產生破壞性影響。在地球上，我們已經進化到可以利用重力來工作。我們的肌肉和骨骼已經發育到可以期待這種力量，並且需要保持它們強壯和健康。在太空中，宇航員無重量地漂浮。這看起來很有趣，但長時間暴露在微重力環境中會對人體產生潛在的影響。

太空旅行對我們的血液循環造成嚴重破壞。人類心血管系統的設計目的是抵抗重力，將血液穩定地泵送到身體周圍，重力通常會將血液拉向我們的腳。但在太空的微重力環境下，血液會向上移動到胸部和頭部，使宇航員的臉浮腫，血壓升高。

肌肉也受到太空旅行的威脅。如果不需要對抗重力，肌肉就會開始浪費，這會增加肌腱炎和脂肪堆積的風險。缺乏重力甚至使宇航員的身高增加了兩英寸，因為背椎骨在沒有重力壓縮的情況下分開，導致疼痛的背痛。

從長遠來看，宇航員會遭受骨質流失的破壞性後果。微重力會導致身體失去鈣和磷，導致骨骼逐漸變弱並增加骨質疏鬆症的風險。骨質流失可能高達每月質量的 1.5%，這大約是在太空停留六個月的 10%，返回地球後至少需要三到四年才能恢復。為了解決這個問題，居住在國際空間站的宇航員必須每天進行 2.5 小時的鍛煉，每週鍛煉 6 次。

*venture（有風險的）企業；投機活動；商業冒險
a new activity, usually in business, that involves risk or uncertainty
She advised us to look abroad for more lucrative business ventures.
There are many joint ventures between American and Japanese companies.

*stall貨攤，攤位；販賣處
a large table or a small shop with an open front from which goods are sold in a public place
In the village market, the stalls are piled high with local vegetables.

*pioneer
先驅，先鋒，創始人
a person who is one of the first people to do something
one of the pioneers of modern science
a pioneer heart surgeon
拓荒者，開拓者，開發者
a person who goes to an area and builds a house, begins a farm, etc.
The pioneers went west across North America, cutting down forests and planting new crops.

*gravity地心引力

*peril巨大的危險；危難，險境
great danger, or something that is very dangerous
I never felt that my life was in peril.
The journey through the mountains was fraught with peril (= full of dangers).
Teenagers must be warned about the perils of unsafe sex.

*micrometeorite微流星體

*vacuum
真空
a space from which most or all of the matter has been removed, or where there is little or no matter
缺乏，空白
a lack of something
The withdrawal of troops from the area has created a security vacuum which will need to be filled.

*lethal致命的；極其危險的
able to cause or causing death; extremely dangerous
Three minutes after the fire started, the house was full of lethal fumes.
In the car the police found guns, knives, and other lethal weapons (= weapons that can kill).
A 59-year-old man was executed by lethal injection (= by having a poisonous substance put into his body) this morning.
That combination of tiredness and alcohol is lethal (= has a very bad effect).

*sturdy
結實的，牢固的；強壯的
physically strong and solid or thick, and therefore unlikely to break or be hurt
sturdy walking boots
a sturdy table
sturdy little legs
堅決的，堅定的
strong and determined
They put up a sturdy defence of their proposal.

*devastating毀滅性的，破壞性極大的
causing a lot of damage or destruction
If the bomb had exploded in the main shopping area, it would have been devastating.
The drought has had devastating consequences/effects.

*prolonged延續很久的

*insidious暗中為害的；潛伏的
(of something unpleasant or dangerous) gradually and secretly causing harm
High blood pressure is an insidious condition which has few symptoms.

*havoc破壞，毀壞；混亂
confusion and lack of order, especially causing damage or trouble
The storm wreaked (= caused) havoc in the garden, uprooting trees and blowing a fence down.
The delay played (= caused) havoc with their travel arrangements.

*cardiovascular心血管的

*puffy（眼睛）腫脹的，腫大的
If the skin around your eyes is puffy, it is slightly swollen.
His eyes were still puffy with sleep.

*tendonitis肌腱炎

*fat accumulation肥胖症

*vertebrae脊椎骨

*phosphorus磷

*osteoporosis骨質疏鬆症

資料來源：劍橋辭典