您好,
Case: 情况（例证,事实）.
eg. In this case time has not been taken into account.
Circumstance:情况（指某事或动作发生时的情况,多用复数）.
eg. The circumstances are now unfavorable to the enemy.
Condition：常用词,用作单数形式,表示人或物目前所处的真实具体状态,尤指内在状态,可与state替用；
eg. The doctor says his condition is better.
用作复数形式时,笼统地表示一般状态.
eg. Conditions have changed greatly since my last visit to his factory.
Position: 有利的状况（如竞争中或战争中的）; (尤作单数)处境,情势（尤指影响某人行为的能力）.
eg.I am not in a position to help you.
Situation: 一般用词,尤指处于某时期的状况,处境,局面,形势.指各种具体情况综合起来的状态,多指危急或重大的事态,强调外部因素对该事态的影响,常用作单数形式. eg. The international situation is favorable to us.
State: 常用词,只人或物所处的外表、心理、健康及所处的情形等方面的情况,但不如condition具体,只用作单数形式.
eg. The house was in a dirty state.
surrounding 多指具体的环境,周围的环境 The building has very beautiful surroundings.也可指抽象的环境,但主要指起影响作用的环境.
希望我的回答对您有帮助,祝您英语进步!