9. That's why I like reading books and studying harder in class.

那就是我在课堂上喜欢读书、学习更刻苦的原因。

That's why...意为"那就是......的原因"，why引导的句子作表语，是表语从句。

E.g. That's why I don't want to leave here.

I got up late, and that's why I missed the bus.

10. I'm shy so it's not easy for me to make friends.

我很腼腆。因此对我来说交朋友不是很容易。

"It's+形容词+for sb. to do sth."是固定结构，意为"做某事对某人来说是......的"。结构中的it是形式主语，真正的主语是后面的动词不定式短语。句中的形容词为描述事物特征的词，如difficult，easy，hard，important，dangerous，necessary，possible等。

E.g. It's very important for us to eat a lot of vegetables every day.

It's dangerous for a child to stay at home alone.

11. But I think friends are like books-you don't need a lot of them as long as they're good. 但是我认为朋友就像书一样--你不需要很多。只要它们好就行。

as long as意为"只要；既然"，引导条件状语从句，主句为一般将来时或含有情态动词can时，所引导的条件状语从句用一般现在时表示将来。

e.g.You can leave here as long as you tell the truth.

You will get good grades as long as you work hard.

12. However, Larry often helps to bring out the best in me.

然而，拉里经常帮助我表现出最好的一面。

bring out意为"使显现；使表现出"。

E.g. I want to bring out the meaning of the poem.我想阐明一下这首诗的意义。

拓展：① bring out还意为"出版；生产"。

E.g. The company is bringing out a new sports car.

② bring out the best/worst in sb. 把某人最好/最坏的一面展现出来

E.g. Please tell me how to bring out the best in me.

13. I don't really care if my friends are the same as me or different.

我真的不介意我的朋友是与我一样还是不同。

if作连词，意为"是否"，引导宾语从句，常用于ask，know，wonder，find out等动词(短语)之后。