You stare at waterfall for a minute or two, then shift your gaze to its surrounding. What you now see appears to drift upward. You __1__ are board a train in a busy station when suddenly another train next __2__ to your starts moving forward. __3__ For a fraction of a second you feel that your train has lurched backward. These optical illusions occur because the brain is constantly matching its model of reality to signals from the body’s sensors and interpret what must be happening – that your train __4__ might have moved, not the other; that downward motion is now __5__ normal, so a change from it must be perceived as upward motion.
The sensors that make this magic are two kinds. __6__ Each eye contains about 120 million rods, which provide somewhat blurry black and white vision. These are the windows of night vision; once adapted to the dark, they can detect a candle burnt __7__ ten miles away. Colorful vision in each eye comes from six to seven __8__ million structures called cones. Under ideal conditions, every cone can “see” the entire rainbow spectrum of visible colors, but one type of cone is most sensitive to red, another to green, the third to __9__ blue.
By monitoring how many wavelength of light affects the different cones, a connected ganglion cell can determine its “color” and relay that data brainwork. Rods and cones send their messages pulsing an __10__ average 20 to 25 times per second along the optic nerve.
答案：
1.surrounding－surroundings。surroundings作為名詞總是以復(fù)數(shù)形式出現(xiàn)，surrounding是形容詞。
2.board－aboard；^board－on。be abroad a train ( a ship, a plane…)意思是“在火車（船、飛機）上”。board 是名詞，可以說be on board （這個改錯之前也出現(xiàn)過，經(jīng)常出現(xiàn)的大家可都要記住啦）
3.you－yours。物主限定詞your不能作介詞的賓語，應(yīng)該用物主代詞yours。
4.interpret－interpreting。Interpret 通過and 和matching并列，所以也應(yīng)該是進行體形式。
5.might－must。根據(jù)上下文，這里必須用表達非常肯定的語氣must，而不是不肯定的“might”，而且，后面的not the other也強調(diào)了非此即彼的肯定性。
6.are^－of。加上介詞of作主語補足語表示對主語的某一種性質(zhì)的描述。
7.burnt－burning。如果用過去分詞burnt修飾candle，那么是說“十英里之外燃盡的蠟燭”，那是不可能用肉眼看到的，所以應(yīng)該改成burning，表示“在燃燒的蠟燭”。
8.Colorful－Color。Colorful是指所修飾的事物本身具有明亮的或者不同的顏色，而color作定語是指修飾的事物使別的事物的各種顏色能夠展現(xiàn)出來，而不是僅僅看到黑白兩色，比如：color television，color photo，color picture等。
9.the－a。the third 表示順序排列，和the first， the second 對應(yīng)，“a third”表示數(shù)量上的增加，和one，another相對應(yīng)。
10. that－those。data這個詞是datum的復(fù)數(shù)形式，所以應(yīng)該用those修飾
The sensors that make this magic are two kinds. __6__ Each eye contains about 120 million rods, which provide somewhat blurry black and white vision. These are the windows of night vision; once adapted to the dark, they can detect a candle burnt __7__ ten miles away. Colorful vision in each eye comes from six to seven __8__ million structures called cones. Under ideal conditions, every cone can “see” the entire rainbow spectrum of visible colors, but one type of cone is most sensitive to red, another to green, the third to __9__ blue.
By monitoring how many wavelength of light affects the different cones, a connected ganglion cell can determine its “color” and relay that data brainwork. Rods and cones send their messages pulsing an __10__ average 20 to 25 times per second along the optic nerve.
答案：
1.surrounding－surroundings。surroundings作為名詞總是以復(fù)數(shù)形式出現(xiàn)，surrounding是形容詞。
2.board－aboard；^board－on。be abroad a train ( a ship, a plane…)意思是“在火車（船、飛機）上”。board 是名詞，可以說be on board （這個改錯之前也出現(xiàn)過，經(jīng)常出現(xiàn)的大家可都要記住啦）
3.you－yours。物主限定詞your不能作介詞的賓語，應(yīng)該用物主代詞yours。
4.interpret－interpreting。Interpret 通過and 和matching并列，所以也應(yīng)該是進行體形式。
5.might－must。根據(jù)上下文，這里必須用表達非常肯定的語氣must，而不是不肯定的“might”，而且，后面的not the other也強調(diào)了非此即彼的肯定性。
6.are^－of。加上介詞of作主語補足語表示對主語的某一種性質(zhì)的描述。
7.burnt－burning。如果用過去分詞burnt修飾candle，那么是說“十英里之外燃盡的蠟燭”，那是不可能用肉眼看到的，所以應(yīng)該改成burning，表示“在燃燒的蠟燭”。
8.Colorful－Color。Colorful是指所修飾的事物本身具有明亮的或者不同的顏色，而color作定語是指修飾的事物使別的事物的各種顏色能夠展現(xiàn)出來，而不是僅僅看到黑白兩色，比如：color television，color photo，color picture等。
9.the－a。the third 表示順序排列，和the first， the second 對應(yīng)，“a third”表示數(shù)量上的增加，和one，another相對應(yīng)。
10. that－those。data這個詞是datum的復(fù)數(shù)形式，所以應(yīng)該用those修飾