1.guard的基本意思是为防御而进行警戒,可指“保护”“守卫”以防外敌侵入,也可指“看守”“控制”以防内部人外逃。引申可指“防范”“严守机密”“警惕”“预防”等。
2.guard多用作及物动词,宾语通常是人,宾语后常接介词from表示“保护某人或某物不受…”; 偶尔也可用作不及物动词,与against连用表示“避免”“预防”。
3.guard的过去分词guarded常用作形容词,在句中可作表语,意为“审慎的”“严守的”。

guard against(v.+prep.)
避免,预防 take precaution to avoid sth
▲guard against sth/v-ing
We must guard against accident.我们必须谨防事故。
We must guard against such a situation.我们必须警惕这样的局面。
Guard against mispronunciation when you learn a foreign language.学外语时要提防发音错误。
You must guard against catching a cold.你一定要防止得感冒。
▲guard sb/oneself/sth against sth
Take this medicine regularly, it will guard you against a return of the illness.按时服此药可防止你旧病复发。
He guarded himself against vice.他避免坏习惯。
Wear a hat to guard your face against the sun.戴顶帽子可以遮阳光。
◇ 用于be ～ed结构
 We were guarded by sentries against surprise attack. 我们由哨兵守卫,以免遭受突然袭击。

guard from(v.+prep.)
保护 keep from danger
▲guard sb/sth from sb/sth/v-ing
I will guard you from all dangers.我会保护你,使你不受任何危险。
The wall guards the place from thieves.围墙保护此地不受盗贼之扰。
This medicine will guard you from a cold. 这种药将会帮助你预防感冒。
The fence along the middle of the road is intended to guard vehicles from crashing into each other.道路中央的防护栏是为防止汽车相撞而设的。

用作及物动词
▲S+～+n./pron.
Three men guarded him whenever he went out.每当他外出时都有三个人保护他。
The soldiers guarded the prince whenever he left the palace.每当王子离开皇宫,士兵们都要保护他。
Two fierce griffins guarded the entrance to the castle.在城堡的进门处,守着两个凶猛的怪物。
It's our duty to guard this bridge and not let the enemy pass.我们的责任是守卫这座桥不让敌人通过。
Guard the secret with your life, tell it to no one!你要以生命来保守秘密,不要告诉任何人。
Guard your temper.克制住你的脾气。
You'd better guard your tongue.你最好说话谨慎些。
◇ 用于be ～ed结构
The player was guarded closely by her opponent.那名运动员被她的对手紧紧地看住。
When they exchanged ideas, their talk was too guarded.在他们交换意见时,说话都很谨慎。
其他
▲v-ing as Adverb.
The boxer is hitting with his right arm, guarding with his left.这个拳击手是用右手出击,左手防护。

guard, defend, protect, safeguard, shield
参见defend条。

1.guard用作不可数名词时,基本意思是指抽象的“守卫”“警戒”“警惕”的行为,引申可作“防御姿势”解。guard用作可数名词时,意思是“卫兵”“哨兵”“警卫人员”,引申还可指“防护装置”。
2.guard既可作个体名词,表示“卫兵”“警卫”“看守”等,也可作集合名词,表示“卫队”“警卫队”“仪仗队”。用作集合名词作主语时,根据上下文,其谓语既可以是单数形式,也可以是复数形式。
3.(the) Guards是“(英国)皇家禁卫军”的意思。

a guard against
防护…的物件 (part of an) article or apparatus designed to prevent injury or loss
Miners wore a helmet as a guard against falling rocks.矿工头戴钢盔,防备落下的岩石。
Reason is a guard against rash action.理智能防止草率行动。

off (one's) guard
毫无防备 unprepared for an attack, a surprise or a mistake
He struck me while I was off guard.他乘我不备打了我。
If you want to persuade the chairman to agree, you'll have to catch him off guard.你要是想说服主席同意,就须乘其不备。

on guard
站岗 on duty
Two soldiers must be on guard all night.必须有两个士兵整夜站岗。
A sentry was on guard at each of the gates.每个大门有一名哨兵站岗。
The soldier who is on guard is my friend.那个站岗的战士是我的朋友。

on one's guard
1.警惕 prepared for an attack, a surprise or a mistake
I should certainly be on my guard if I were you.我要是你肯定会保持警惕。
2.防备… defence sb/sth
▲on one's guard against sb/sth/v-ing
Be on your guard against thieves.当心小偷。
We shall have to be on our guard against making mistakes like that in the future.我们今后必须防止发生类似错误。

stand guard over
守卫 act as a sentry
The mother bear stood guard over her injured cub.母熊守卫着那只受伤的小熊。

All the prisoners are under close guard.所有的犯人都在严密的看守之下。
His guard was down.他放松了警惕。
He wears the guard on his expression.他脸部带有戒备的神情。
He dropped up his guard.他未作出防御姿势。
The guard won't ler you in if you don't show him your pass如果你不出示通行证,卫兵不会让你进去的。
A guard is made of eight soldiers.卫队由八名士兵组成。
At the grand welcoming cermony at the alrport the president reviewed a guard of honour made up of men of the fighting service.在机场的隆重欢迎仪式上,总统检阅了三军仪仗队。
The guard of honour are gathering.仪仗队正在集合。
The camp guards are exchanged every night.野营的警卫人员每天晚上调换。
The guard of the train blew his whistle.火车上的列车员吹哨子。
Football players often wear shin guards.足球运动员经常穿着护腿。
His brother is a Guards officer.他的哥哥是个英国皇家禁卫军军官。

guard, guardian
这两个词都有“看守者”“守卫者”的意思。其区别是:
1.guard的目的是为了防止、防御危险或攻击,防止犯人逃跑、闹事等; 而guardian指捍卫或保卫某种信仰、自由、主义等。例如:
He effected his escape by slogging a guard.他猛击了一名看守,然后成功地逃跑了。
A minister or a priest is considered a guardian of faith.牧师和教士被认为是信仰的护卫者。
2.guardian还可指法律上所承认的某人的“监护人”,而guard则没有此义。例如:
Mr. Smith is the guardian of that boy.史密斯先生是那个孩子的监护人。
3.guard的复数形式guards常指警卫队,而guardian则没有此用法。

1.所有犯人都受到严密的警戒。
［误］  All the prisoners are under a close guard.
［正］  All the prisoners are under close guard.
如果我们放松了警惕,就会被欺骗。
［误］  If we drop our guards, we shall be fooled.
［正］  If we drop our guard, we shall be fooled.
［析］  guard作“警戒”“警惕”解时,是不可数名词,前面不能加不定冠词,后面不能加-s。
2.他们在没有戒备时被敌人抓住。
［误］  They were caught without guard by the enemy.
［正］  They were caught off (their) guard by the enemy.
他们尽力保持警惕。
［误］  They did their best to keep with their guard.
［正］  They did their best to keep on their guard.
［析］  表示“没有警惕”“毫无准备”时,应该用off (one's) guard,而不是without guard; 相应地,表示“保持警惕”应该用onone's guard而非with guard。

在英式英语中, guard可作“列车员”解,而在美式英语里这个意思通常用ｃｏｎｄｕｃｔｏｒ来表示; guard作“监狱看守员”解时,通常见于美式英语,英式英语多用warder。

［同义词］ v. defend, preserve, protect, shield n. patrol, sentinel, sentry, watchman
［反义词］ v. disregard, ignore, neglect
［词源］  ＜中古英语garde (保护,警卫,保卫)