brain Your brain has two parts:the left & the right.Your lef

C,give sb a hand 是帮助某人的意思
这句话的意思是Brain是如此之好他经常在遇到困难时帮助我.
其他的选项都没有帮助的意思

这是个Pun吧...
你的大脑有两部分, 左边和右边. 左边没有任何东西是对的, 右边里面没有剩下任何东西...
right( 右边或者真确的意思.) left(左边或者余下,剩下的意思)
其实就是拐着弯说人蠢吧= =

spent on 是一个词组 用于 投资于的意思
后面in vain 是一个词组 徒劳 白费的意思
in是和vain搭配

后面用了will,if从句后用将来时

Researchers are constantly performing studies and research to find out more about the brain.A human brain is extremely complex and although we have learned a great deal about the brain,there is still a lot more that remains unknown to doctors and researchers.In recent years,scientists have found hypnosis to be very useful in learning more about the human brain.
The human brain is in charge of the body's nervous system,sensory system,motor system,and behavior.Basically,the brain is in charge of everything that occurs in your body.It is a very important organ and because it is so complex,it makes it difficult to study.
In 2002,a study was performed on 10 participants.The participants received 8 positron emission tomography (PET) scans,4 before hypnotic induction and 4 after the induction of hypnosis.Participants were evaluated by their level of mental relaxation and absorption.The study found that hypnosis increases occipital regional cerebral blood flow.This leads to increased mental absorption.The study also confirms that hypnosis decreases cortical arousal.These areas of the brain control consciousness and this study confirms that hypnosis has an effect on consciousness
According to a New York Times article,neuro-scientists are using hypnosis to study the brain.In one study,researchers were able to take highly suggestible people and change the way they perceived things.This study consisted of 8 highly suggestible people and 8 people who had very low suggestibility to hypnosis.They were all given the same suggestions,having to do with color,under hypnosis.Later,brain scans were performed on all the participants and those who were highly suggestible had noticeable differences in their brain scans in the area of the brain that recognizes color
In 2008,a study on the brain of patients under hypnosis revealed insight into the neural circuitry of the brain.Brain scans were performed on highly suggestible people and non-suggestible people after hypnotic induction.Researchers were able to learn a lot about memory,recall,and amnesia in relation to brain functioning.Hypnosis can model amnesia and is allowing scientists to learn more about the brain
These studies show that hypnotherapy can teach neuroscientists a lot about the brain.Hypnosis is a natural and safe method to use in order to learn more about the brain and more research should be performed using hypnosis.

血液为身体各器官提供养份,大脑也需要血液.

我们想同意比较电视和电脑最近的报告之间的差异：当你使用一个你把你的大脑,以你关掉它.

可能我短路了（应该是带有自责的语气吧）

a case for your brain
google只搜索到1个词条,确定是这样吗?
按照字面翻译,脑部的病情.连起来,你脑部的病情严重吗?

slow改成slowly

http://www.***.com/html/qDetail/03/c2/201207/r2m5c203135929.html
人有大脑.他认为,学习和说话.科学家曾认为,人与动物不同,因为人类能够思考和学习.如今他们知道,狗,猫和鸟可以学习,太.所以他们认为人与动物不同,因为他们能说.而动物能与# 039；T.当他们害怕的动物发出噪音,或不高兴.猿甚至可以站在一些事情比男性更快.其中的一个或两个已经学会了几句.但它们不加入的话来句子.不能像我们一样思考,因为它们没有语言.语言是一种很奇妙的东西.在它的帮助下,人可以做任何事情,即使是我们的现代世界.每一个孩子都能SP他的语言很好当他是四或五,但没有动物学会说话.儿童是怎样学习呢?科学家不知道.他们只知道人会说是因为他有一个大脑.

我们将不得不用我们的大脑去思考它们或采取比我们所知更多的行动

答案是：
“The （adult） human brain weighs （on average） about 3 pounds （lb）or 1.5 kilograms (kg）. " 成人的大脑的重量大概是3磅 （1.5 公斤）左右.
还可以加上：”It is around 2% of the body weight“ 它大概等于体重的百分之2.
希望帮到你.

直译是：他的大脑就只有豌豆那么大.
意思是：他做事没脑.

leave your brain/mind at the door来自于句子“leave your coat at the door",原句的意思是你进入了某个旅店或者戏院的门,你把外衣脱下来放在门口处,因为走进房间里之后你就不需要外衣了.直到你走出房间之前,你才到门口处取回你的外衣.
将coat换成brain或者Mind,就是“把你的脑子放到门口”,即从现在开始,你不需要用你的脑子了,也就是表达“别去想了,不用多想”的意思.

这是在玩文字游戏,right和left分别为多义词.right有右边和正确的意思,left有左边和剩下的意思.所以全句直译的话可以是：
大脑有两部分,左脑和右脑.左脑里没有什么是正确的,而右脑里则什么都没有.

It keeps your brain on its toes.
我想在这段话里可以翻译作：
让你的大脑保持精神振奋 让你的保持思维敏捷.
词典上查到这个短语：
keep sb.on their toes（通过出其不意的行动）使保持警觉
希望这些能帮到你