A decision is a choice made from among alternative courses of action that are available. The purpose of making a decision is to establish and achieve organizational goals and objectives. The reason for making a decision is that a problem exists， goals or objectives are wrong， or something is standing in the way of accomplishing them.
1.made from among alternative courses of action 是过去分词短语作定语
courses of action 行动方针
that are available 是定语从句，修饰概念短语“行动方针”
2.The reason for making a decision is that a problem exists， goals or objectives are wrong， or something is standing in the way of accomplishing them.
此句是由that引导的表语从句，表语从句由a problem exist; goals of objectives are wrong;
及something is standing in the way of accomplishing them三个并列句构成。
The reason for … is that 是一个常用的句子。例： The reason for canceling the travel is that
they lack of money. 取消旅行的原因是他们手头缺钱。
The reason why … 是另外一个常用的句子。例：There are 3 reasons why they are unwilling to discuss insurance .他们不愿意谈论保险的原因有三个。
Thus the decision-making process is fundamental to management. Almost everything a manager does involves decisions， indeed， some suggest that the management process is decision making. Although managers cannot predict the future， many of their decisions require that they consider possible future events. Often managers must make a best guess at what the future will be and try to leave as little as possible to chance， but since uncertainty is always there， risk accompanies decisions. Sometimes the consequences of a poor decision are slight; at other times they are serious.
3.a manager does是省略that的定语从句，修饰先行词everything
当先行词为everything， something， anything， nothing等不定代词时定语从句引导词不可用which， 此句的后半部分 some suggest that …… 是宾语从句suggest v. 认为，提出，建议(其后的宾语从句多用于虚拟语气)
例如：Although my car is very old，it still runs very well .
require vt. 要求，需要 后边由that引导一个宾语从句
5.Often managers must make a best guess at what the future will be and try to leave as little as possible to chance， but since uncertainty is always there， risk accompanies decisions.
make a best guess at 作出最佳猜测，at 表示动作或行为的方向和目标，如：look at (看) ，aim at (瞄准，目的是)，throw (a stone) at (向…掷石头)，shoot at (射击)，laugh at (嘲笑)
本句中what the future will be 是一个介词宾语从句，(作介词at 的宾语);
to leave sth. to chance “凭运气，听任命运的安排，听其自然发展”
“as + 形容词(或副词)+ as possible”意思是“尽可能地…; 尽量”。
as little as possible 尽可能少
I tried to be as friendly as possible. 我尽量地表示友好。
Come as quickly as possible. 尽快来。
since uncertainty is always there 是一个原因状语从句。
risk accompanies decisions .风险伴随着决策
6.sometimes … at other times 有时… ，而有时则 …
a poor decision 一个不良决策