see有“看”或“看到”的意思，是個通用詞，使用範圍最廣。see的使用範圍雖然最廣，但作為“看”的含義，不用於祈使句。
Look,he's coming.
看，他來了
Watch him.Don't let him escape.
看著他，別讓他逃掉了
As soon as he saw us,he picked up a long pipe which was covered with coins
他壹看到我們就拿起了壹根鑲有硬幣的長長的管樂器
observe和notice都有“看到”或“註意到”的意思，但observe強調“留心觀察”。
The search proved difficult,for the puma was often observed at one place in the morning and at another place twenty miles away in the evening.
搜捕工作證明是很困難的，因為人們看到的這只美洲獅常常是早上在壹個地方，而晚上又在二十英裏之外的另壹個地方。
In 1948,he went to lake Kivu in the Congo to observe a new volcano which he later named Kituro.
1948年他到岡果的基烏湖去觀察壹個新的火山，後來他把這座火山命名為基特羅。
而notice則包含著“偶然看到”的意思，其內涵是“看到目的物後要作出反應”。如：看到熟人常常打個招呼，看到壹件事後在腦中進行判斷。
…I happened to be walking in my garden when I noticed a huge number of snails taking a stroll on some of my prize plants.
……我偶然在花園裏走著走著，突然看到許多蝸牛在我的壹些心愛的植物上悠閑地爬著。
note和remark比notice更強調所看到的事物給大腦留下的印象
After consulting my railway time-table,I noted with satisfaction that there was an express train to Westhaven.
我翻閱了鐵路時刻表，見有壹班去韋斯赫溫的快車，甚為滿意。
remark有時包含“評論”的意思。如：這部新拍影片的突出的獨到之出受到了壹些評論家的註意。此句中的“註意”用remark是很確切的
This outstanding originality of the newly-made film has been remarked by some critics.
這部新拍的影片的突出的獨到之處受到了某些評論家的註意。
peer的含義是半瞇著眼睛好奇地或吃力地細看，尤其是透過例如暮色之類的媒介，或站在遮擋物後面而註目凝視；這種凝視只是對視覺器官的使用，但未必能夠看得到
Old women in black shawls peered at us from door-ways.
頭上帶著黑頭巾的老婦人從門廊裏瞅著我們。
如果經過了壹定時間的如此細看最終看到了目的物，那麽這個動作便可以用discern來表示了，在口語中，常用詞是make out
We discerned the figure of a man clinging to the mast of the wrecked ship.
我們費力地看到了壹個人影，懸浮在遇難船只的桅桿上。
In the breaking and remarking,in the timing,interweaving,beginning afresh,the writer comes to discern things in his material which were not consciously in his mind when he began.
在作家的思路中斷重新構思的時候，在安排時間、揉和內容、重新開始的時候，逐步領悟到自己素材中的內容，而這些東西在他動筆時心中並不清楚。
watch 表示“觀看”或“監視”的意思，壹般目的物應處於運動狀態。
One day there were fewer people in the shop than usual when the woman came in,so it was easier for the detective to watch her.
有壹天，當那個婦女進來時，該店裏的人比通常少壹些，所以偵探比較容易監視她。
相關資料供參考：
1、《美國傳統雙解詞典》“observe”詞條：
observe,keep,celebrate,commemorate,solemnize
These verbs are compared as they mean to give proper heed to or show proper reverence for something, such as a rule, custom, or holiday.
當這些動詞都表示給予壹定註意或對某些事物，如對規定、習慣、或節日表壹定尊敬時。
Observe stresses respectful adherence,as to law or tradition,often in the form of compliance with prescribed rites:
Observe 強調尊敬性的遵從，如對於法律或傳統，常常以遵守規定的禮儀儀式為形式：
observe the speed limit;
遵守速度限制；
observe the Sabbath.
信守安息日。
Keep contrasts withbreak and violate; it implies actions such as the discharge of a duty or the fulfillment of a promise:
Keep 相對於break 和 violate； 它暗含有如未盡職責或沒有實現諾言等行為：
He said he would help, and he kept his word.
他說過要幫忙的，他兌現了。
Celebrate in this comparison emphasizes observance in the form of rejoicing or festivity:
Celebrate 在這項比較上強調以歡樂或喜慶形式的遵從：
We are planning a surprise party to celebrate her birthday. Tocommemorate is to honor the memory of a past event;
我們正為他的生日而準備著壹個驚奇的派對。 而commemorate 是對過去的事件的記憶的尊敬；
solemnize implies dignity and gravity in the celebration of an occasion:
solemnize 暗含某壹慶祝場面的莊重和嚴肅：
“It [July 2, 1776] ought to be commemorated as the day of deliverance . . . It ought to be solemnized with pomp and parade . . .from one end of this continent to the other, from this time forward forevermore” (John Adams).See also Synonyms at see [1]
“它〔1776年7月2日〕 應作為誕生之日來紀念…… 應用壯觀的典禮和遊行來隆重慶祝……從這片大陸的這頭到那頭，從此時到永遠” （約翰·亞當斯）參見同義詞 see[1]
2、《美國傳統雙解詞典》“see”詞條第1項：
see,behold,note,notice,espy,descry,observe,contemplate,survey,view,perceive,discern,remark
These verbs refer to being or becoming visually or mentally aware of something.
這些動詞指視覺上或精神上意識到某物。
See, the most general,can mean merely to use the faculty of sightbut more often implies recognition, understanding, or appreciation:
See 是最常見的，它可以只指用視覺器官，但更經常暗示發現、理解或明白：
“We must ... give the image of what we actually see” (Paul Cézanne).
“我們壹定會對我們看到過的東西留下印象” （保羅·塞尚）。
“If I have seen further (than ... Descartes) it is by standing upon the shoulders of Giants” (Isaac Newton).
“如果我已經（比迪卡爾）看得更遠，那是因為我站到了巨人的肩膀上” （伊薩克·牛頓）。
Behold more strongly implies awareness of what is seen:
Behold 更強烈地暗示對已被看見的某物的意識：
“My heart leaps up when I behold/A rainbow in the sky” (William Wordsworth).
“當我看見天邊的壹道彩虹時，我的心不由地跳了起來” （威廉·渥茲華斯）。
Note andnotice suggest close observation and a rather detailed visual or mental impression;
Note 和notice 指密切地觀察和提供更具細節和視覺或精神印象；
note in particular implies careful, systematic recording in the mind:
note 特別暗示思想中仔細的、系統的記錄：
Be careful to note where the road turns left.
註意道路左拐的路標。
I have noted and overridden your protests.
我已經註意到並推翻了妳的抗議。
She didn't notice the run in her stocking until she had arrived at the office.
她到了辦公室才註意到襪子抽絲了。
I notice that you're out of sorts.
我註意到妳心情不好。
Espy anddescry both stress acuteness of sight that permits the detection of something distant, partially hidden, or obscure:
Espy 和descry 都強調視覺察覺遠處（尤指被掩藏的或不清楚的）物體的精確性：
“espied the misspelled Latin word in [the] letter” (Los Angeles Times);
“發現在〔這個〕 字母中拼錯的拉丁字” （洛杉磯時報）；
“the lighthouse, which can be descried from a distance” (Michael Strauss).
“很遠就能看見那座燈塔” （邁克·施特勞斯）。
Observe emphasizes careful, closely directed attention:
Observe 強調仔細、密切地直接觀察：
“I saw the pots . . . red-hot . . . and observed that they did not crack at all” (Daniel Defoe).
“我看見缸子…又紅又熱…而且發現它們根本就不會破裂” （丹尼爾·狄佛）。
Contemplate implies looking attentively and thoughtfully:
Contemplate 暗示專心而且徹底地看著：
“It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes” (Charles Darwin).
“觀賞長滿各種植物，鳥兒在灌木叢中唱歌的雜亂河堤極為有趣 （查爾斯·達爾文）。
Survey stresses detailed, often comprehensive examination:
Survey 強調仔細地、經常是全面的檢查：
“Strickland looked away and idly surveyed the ceiling” (W. Somerset Maugham).
“史蒂蘭向別處望去，懶懶地掃視了壹遍天花板” (W·薩默塞特·毛姆）。
View usually suggests examination with a particular purpose in mind or in a special way:
View 通常暗示以壹種特殊的方式或帶有特定的目的去觀察：
The medical examiner viewed the victim's body.
法醫檢驗了受害者的屍體。
“He [man] viewed the crocodile as a thing sometimes to worship, but always to run away from” (Thomas De Quincey).
“他〔人類〕 把鱷魚看成可以崇拜的東西，但又經常從鱷魚那兒逃離” （托瑪斯·德·昆西）。
Perceive anddiscern both imply not only visual recognition but also mental comprehension;perceive is especially associated with insight, anddiscern, with the ability to distinguish, discriminate, and make judgments:
Perceive 和discern 兩者都不僅暗示視覺上的識別， 而且暗示思想上的理解；perceive 尤其與洞察力相關， 而discern 則與辨別、區別及判斷能力相關：
“We perceived a little girl coming towards us” (Frederick Marryat).
“我們辨認出壹個小女孩朝我們走來” （弗雷德裏克·馬裏亞特）。
“I plainly perceive [that] some objections remain” (Edmund Burke).
“我明白地看到〔連接詞〕 還有壹些反對者” （埃德蒙·伯克）。
Even with a magnifying glass I couldn't discern any imperfections in the porcelain.
即使有壹個放大鏡，我也不能發現瓷器上的任何瑕點。
Many in the audience lack the background and taste to discern a good performance of the sonata from a bad one.
許多聽眾不了解文化背景和缺乏審美情趣，不能區分奏鳴曲表演的優劣。
Remark suggests close attention and often an evaluation of what is noticed:
Remark 暗示密切地註意和經常對所觀察的事物進行估價：
“Their assemblies afforded me daily opportunities of remarking characters and manners” (Samuel Johnson).
“他們的集會給了我每天觀察其性格和禮儀的機會” （塞繆爾·約翰遜）
3、《用法詞典》“see”詞條第1項：
see,catch sight of,spot
see的意思是：經過有意識地使用視覺器官才能“看到”
I haven't seen you for a long time.
很久沒有看到妳了。
而catch sight of 的意思是：被看到的東西進入了眼簾，而不是有意識地使用視覺器官
The bull was busy with the matador at the time,but it suddenly caught sight of the drunk who was shouting rude remarks and waving a red cap.
當時那公牛正忙著與鬥牛士搏鬥，但是它突然看到了那個醉漢，而那醉漢正在說些粗魯的評論話，而且揮舞著壹頂紅色的帽子。
Don't let me catch sight of you doing it again!
別讓我再看到妳幹這種事了！
spot的含義是從同類的事物中認出某壹個來，或從人群中認出某人來(to single out)；或者表示“察看到”，這時被看到的目標處於壹定背景中，而此目標好象壹個點壹樣。
a wild animal had been spotted forty-five miles south of London
在倫敦以南45英裏處有人看到了壹只野獸。
The teacher spotted a mistake in his home work.
老師在他的家庭作業中看出了壹個錯誤。
He spotted his friend in the crowd.
他從人群中認出了他的朋友。