Taking a book from a bookcase, I climbed up into the window-seat.
这句中的taking a book from a bookcase是现在分词短语，在句中作时间状语，taking的逻辑主语是I，这一现在分词短语的作用相当于一个时间状语从句，也就是说After I took a book from a bookcase ...。

I prayed that I should not be discovered.
should在这里表示说话人的意愿，是一个情态助动词。

But Eliza was quicker than John.
这句中quick根据意思可以理解为“脑子动得快、反应快”，例如：
a quick mind 聪明的头脑
be quick of hearing 听觉灵敏

What do you want?
What do you want 是口语的说法，意思是“有什么事”。

"Say 'What do you want, Master Reed'," was his reply.
这句话中用了直接引语，整个句子采用了倒装结构，为了突出所说的话。如果不倒装，句子应该是：His reply was "Say 'What do you want, Master Reed'."
直接引语中是一个祈使句，表示命令的口吻，而这个祈使句中又含有一个直接引语，所以引语开头的What第一个字母要大写。

He was big and stout for his age, with a large face and an unhealthy skin.
for his age意思是“对于他的年纪来说”；介词with在这里的意思是“长着”；unhealthy原意是“不健康的”在这里的意思是“苍白的”。

...,he spent about three minutes in putting out his tongue at me.
注意，spend time in doing sth.这一句型；about这里的意思是"大约"；put out one's tongue at sb.是一种羞辱别人的行为和动作。
介词at表示“冲着、对着”，课文中类似的用法如：
He was going to throw the book at me.
He ran at me ...

Then he hit me suddenly and hard.
这里hit的意思是“打”。hit是个不规则动词，原形动词和过去式以及过去分词都是同一形式：hit。
hard在这里的意思是“使劲地”，作副词。

You have no business to read our books.
business在这里的意思是“权利”，相当于right的意思。business的其它意思：
It's a teacher's business to make children learn. 教师的职责是促使孩子们学习。
What a business it is! 这真是一件麻烦事！（这里的business作“麻烦的事情”讲）
It is no business of mine. 这事与我无关。（business作事情讲）
Business is business. 公事公办。（business是公事）

You ought to beg, and not live with a gentleman's children.
ought to是情态助动词，and后面是有省略的并列分句，其完整形式应该是：You ought not to live with a gentleman's children. ought to的否定式是ought not to。
注意，这里gentleman的含义不同于社交用语里的“先生”，它在英国维多利亚时代专指有身份、地位的人，有身份的女人可以说gentlewoman。

I was knocked over and fell against the door, striking my head and cutting it badly.
knock sb. over意思是“把某人撞倒在地上”，这里是被动语态的用法。
and后面是一个并列分句，主语仍然是I，但谓语动词不再是被动语态。 fell是fall的过去式，介词against在这里的意思是“对着”。
striking和cutting都是现在分词，表示伴随情况的结果，所以不能理解为主动的行为。
badly在这里的意思是“严重地、厉害地”，是一个程度副词。

"For shame!" cried the maid. "To strike a gentleman, your young master!"
直接引语出现在句首时，说话人和引语动词的词序可以颠倒，比如cried在这里放到了the maid的前面。
to strike a gentleman是一种表示惊叹的形式，有“竟然……”的意思。
your young master是gentleman的同位语；for shame是习惯说法，意思是“真不害臊，真不像话”。意思相似的句子还有：Shame on you!

"You ought to know, Miss," said the nurse, "that you owe much to Mrs. Reed. She keeps you. If she turns you away, you will have to go to the Poor-house."
1）the nurse指的是the maid，在这里意思相同，都是女佣。
2）you ought to know应当和后面的that从句，看成是一个完整的句子。
3）Miss是称呼语，在这里作插入成份，不做know的宾语；owe sth. to sb. 是一个习用短语，在这里的意思是“应该好好感激某人”。例如：
She owes her success to hard work. 她把她的成功归于勤奋工作。
I owe my life to you. 多亏了你，我才活了下来。
4）much在这里的词性是名词；keeps在这里的意思是“收养、收留”；turn sb. away 意思是“把某人打发走”。例如：
Please don't turn your head away when I'm talking to you. 我跟你说话的时候，别把头转过去。（这里turn away是“转过去”的意思）
They turned the talk away from that. 他们撇开了那个话题。

NOTES TO THE DIALOGUE

Booking a Room 预订房间
及物动词book表示“预订”。还有一个动词也表示“预订”：reserve a room。
book的用法：
He booked two seats in that restaurant. 他在那家餐馆订了两张座位。
The flight is fully booked. 这次航班的票全已订完。

How much is the room?
同样的意思还可以这样说：What's the rate? / What's the charge?