I think:

1

a.They paid $25 000 for school fees, so they must work in a really long time to take it back.

the in is not necessary. take it away.

b is ok.

2. are there differences if I say

concept is the idea and content is the story in a movie.

get means you do not have a dog, have and keep means maybe you already have one, "bring up a dog" is weird.

pay rate is corret i think

3 Is there a saying like that in English?

4 I think you can just ignore him.

The question is not who loves you, but who you love.

Or maybe you are just looking for someone who loves you, rather than someone you will give up your life for.

Then, it doesn't really matter whether he loves you or not.

But if you meet someone who you do not mind him forgetting your birthday, then that's true love. And the love is yours.

That means you do understand the language but cannot use it, which means you maybe need practice on speaking it or writing it. Personally I think watching movies can help you get into the situation and speaking to native speakers, if you got the chance, is even better. But still, it'll take time.

方言是非常重要的文化遗产，我是一定会教的。

其实我们这一代已经遗失了很多方言中的词语啊习语之类的东西。

就像全中国的城市都长得差不多一样，要是全中国人都只会说普通话了，方言都死了，那这个国家该是多么无聊啊。

夜は3～６時間で午後１時間です。

今の社会でしょうがないです。

毎日眠くて過ごします。

Which option is correct? and why?

"Drop her off" or "drop off her"
Pick him up or pick up him
find out something or find something out

My guess:

drop her off and pick him up.

because "him" and "her" are pronouns, if they are nouns like "the boy"

then both "pick the boy up"  and "pick up the boy" are ok.

日本語の言葉使いが面白いと思います。　単語選びなんで。

そして日本語で話をする時のあの強い気持ちも面白いです。