解读：
Aggressive behavior is any behavior that is intended to cause
injury, pain, suffering, damage, or destruction. 后面的五个并列名词只挑一个简单的去读就行了，读成Aggressive behavior is any behavior that is intended to cause
injury。
While
aggressive behavior is often thought of as purely physical, verbal attacks such as screaming and shouting or belittling and humiliating comments aimed at causing harm and suffering can also be a type of aggression. What is key to the definition of aggression is that whenever harm is inflicted, be it physical or verbal, it is intentional.遇到wihle，就找后面的逗号，因为wihle后面一直到verbal attack之间的内容，和verbal attack后面的内容是转折关系。while表示让步，所以可以理解为把while去掉，后面的逗号换成but。就成了aggressive behavior is often thought of as purely physical
but
verbal attacks.....看到没有，作者实际上想强调的是but后面的，或者是逗号后面的，所以只从verbal attacks开始读就可以了。verbal attacks后面有such as，就只读such as 前面的名词。后面的名词全部省略不读，一直到can also be...所以应该读成verbal attacks can also be a type of aggression. What is key to the definition of aggression is that定义攻击性行为的关键在于whenever harm is inflicted, 不管什么时候造成伤害，be it physical or verbal, 不管是物理上的还是口头上的伤害，it is intentional.关键是故意的。
Questions about the causes of aggression have long been of concern to both social and biological scientists.攻击性行为的起因长期困扰了social and biological scientists.文中both提醒下面会说道两种情况，并且可以猜测出重点会讲到起因。外国人的思维是总是文中直接给出观点，而不是说一大堆无用的铺垫，最后再引出观点。或者可以是先直接给出观点，然后再说一大堆说明性语言。所以首句就是表明观点的句子，很重要。 尤其是在议论文中，每段第一句话通常都暗示此段会讲到什么，文中首段通常表明作者观点。
Theories about the causes of aggression cover a broad spectrum, ranging from those with biological or instinctive emphases
to those that portray aggression as a learned behavior.你看，开始讲起因了。spectrum不认识，看后面，ranging 分词做后置定语。逗号前后两个句子是顺承关系。ranging后面整句话都在解释broad spectrum，解释为ranging from ...... to ......。文中两个those都是指代theories。此句就很容易理解了。.....的起因很广，从....理论到描述攻击性行为为一种后天学习的行为的理论。biological or instinctive emphases中两个名词是并列关系，所以不认识instinctive emphases不要紧，只读biological就可以了。所以，此段讲了两个起因，instinctive先天的和learned后天的。
Numerous theories are based on the idea that aggression is an inherent and natural human instinct. 此段首句看出开始介绍第一种起因，即先天了。and连接的两个名词表示并列，只读一个就可以了。
Aggression have been explained as an instinct that is directed externally toward others in a process called displacement,此句中的called怎么处理?called直接想成等号。process就叫displacement。displacement就叫process。这是ETS喜欢玩的文字游戏之一，用几个复杂的概念来表示一个简单的概念。that后面是定语从句，是解释前面一句话的，可读可不读。一眼跳过即可。
and it has been noted that aggressive impulses that are not channeled toward a specific person or group may be expressed indirectly through socially acceptable activities such as sports and competition in a process called catharsis. aggressive impulses
这个概念就是aggression的意思。注意，这是文字游戏。注意到.....不是朝着个人和group，是不直接表现出来的在社会上可以被接受的一种行为。
Biological or instinctive, theories of aggression have also been put forth by证实 ethologists, who study the behavior of animals in their natural environments. 定语从句不读。
A number of ethologists have, based upon their observations of animals, supported the view that aggression is an innate instinct common to humans.句子中间被断开，直接把前面的和后面的连起读，两个逗号中间的不管。读成A number of ethologists have supported the.....