我也上过这种培训

他们提出的第一个问题是，身为TA 你到底应该以朋友的立场，还是老师的立场面对学生。

这里说的也是这种培训里面提出的一个问题，如何面对学生家长。。。

I was equally shocked (as I sat in a seminar for 500 first-year teaching assistants )and was told what to do (when Mom and/or Dad show up in your office complaining about the marks or assignments that you have given to their children.)
主干是I was shocked and was told what to do.两个括号是两个状语从句，第二个稍微麻烦点，单独分析从句：带伴随状语complaining和定语从句that.

“I was equally shocked”是主系表结构，“as I sat in a seminar for 500 first-year teaching assistants”是时间状语从句，“and was told what to do”与前面的“was shocked”并列，“when Mom and/or Dad show up in your office complaining about the marks or assignments that you have given to their children”是时间状语从句。
整句话的翻译是：当我坐在一个有 500 名一年级教学助理参加的研讨会上，被告知当妈妈和/或爸爸出现在你的办公室抱怨你给他们孩子的分数或作业时该怎么做时，我同样感到震惊。

以上分析均不对