I realized( )there were some things I had not ye

1.It was not ____ he took off his dark glass ____ I realized who he was.
第一个填UNTIL 可是第二个空里为什么不能填写THAT 而答案给的是WHEN
请问有明白的朋友告诉我吗?
请问什么地方可以分析出一个句子是状语从句呢 我就是不会看句子 能给我讲讲吗?

It was several years ----- I realized ---- David had lied to me.
A.when.what
B.that.when
C.before.that
D.until.why

when与until
We had been driving for hours _________I realized that something was wrong with one of the tyres.
填when还是until呢?

It was not until he took off his dark glasses __I realized who he was.
A.when B.that

When I noticed the puzzled look on his face, I realized that he didn't understand me
句首的when为什么不能用until代替

when I locked the door,I realized I ( ) my key at home.
这里填 left 还是 had left ,或者二者均可为什么?

When my hand touched the letter in my pocket,I realized that I had forgotten _____ it.

[ ]

A. to post B. to have posted C. posting D. having posted

英语翻译
When I thought about writing this essay,I realized that the value of teaching is surely different to each of us,and second only to the value of learning.
It has been my experience that the teachers who most enjoy their subject,and who most care about their students are those who make the best teachers --- the ones whom I most remember.My favorite teachers throughout elementary school,high school and now college are the few that I remember as sharing their knowledge of a given subject,not just teaching the textbook.These are not the teachers who assign a chapter’s worth of reading and answer the review questions at the end of the chapter.They know their subject inside and out,enjoy the subject,and truly love sharing it with others.They want to open their world of knowledge to their students,whether they are young or old.
The value of teaching,to me,is the opportunity it provides the teacher to watch the students grow and expand their horizons based on interest,energy,knowledge,and experiences shared in the classroom.Hands-on projects will stay with them longer than just hear-say wisdom or reading a textbook.This is the kind of teacher I want to be.I want to make history come alive in my classroom for each individual who sits in on my class.
The value of teaching from a student’s view is the opportunity learning provides to open new world to himself or herself with the curiosity to explore whatever is interesting.It is the opportunity for parents provide information to their children through people other than their own personal knowledge and experiences.
In closing,it is my belief that the value of teaching touches everyone,always.Where there are teachers,there will be students.The world must never run out of teachers,for we must never stop learning.