英语句子的语法结构Once in a while I cried out of frustration,and some

英语句子的语法结构
Once in a while I cried out of frustration,and sometimee I felt like giving up .But I didn't feel intimidated by students who spoke faster than I did because I took all the time I needed to think out my ideas and wrote a reply before posting it on the screen.
试分析此句子详细的语法结构及其含义,

“我偶尔会因为受挫而哭泣,有时也会想要放弃.但我没有因为其他学生发言比我迅速而畏缩,因为只要有时间我就会构思自己的想法,然后把我的回复贴出来.”
1.Once in a while I cried out of frustration,and sometimes I felt like giving up
I cried and I felt like giving up 是主干,其他的Once in a while 偶尔,out of frustration因为 受挫 sometimes 都是状语
2.But I didn't feel intimidated by students who spoke faster than I did because I took all the time I needed to think out my ideas and wrote a reply before posting it on the screen.
I didn't feel intimidated 是主干,by students who spoke faster than I did 是一个含有定语从句的状语部分,
because I took all the time I needed to think out my ideas and wrote a reply before posting it on the screen 是原因状语从句
其中I took all the time and wrote a reply 是主干,I needed 是定语,to think out my ideas 是补语 before posting it on the screen 时间状语从句
再问： 那第二句开头的but作什么用呢?but是并列连词，是用来连接并列句的啊？这里没有两个句子，只有一个！那这里的but岂不是多余？还有 and wrote a reply 可不可以与to think out my ideas 并列呢？
再答： 这里就是两个句子，因为 1. 。。。。I felt like giving up后面是句号。 2. But。。。。首字母大写 所以but 引起的是第二个句子。前一句说都有放弃的想法了。第二句转折，说最终还是没有被别人的表现吓退，还是会努力的。 but可以引起一个句子中的两个部分，也可以单独引起一个句子，就像这里一样。 and wrote a reply是和took all the time I needed 并列的，因为两个都是过去时，而to think Out my ideas是took all the time I needed 的目的状语
再问： 那took all the time I needed 中的 I needed 是什么从句，怎么没有连接词？
再答： “花我需要的所有时间”，i needed 是定语从句，连接词是that，可以省略，因为先行词all the time在定语从句中是i needed得宾语，所以连接词可以省略， 如果是主语，that就不能省略了，比如took all the time that was available to me