I'm very confused! (Girls are happier in the country than ... in the city)

[Vaok]

１.Girls are happier in the country than ＿＿＿in the city.
A. that B. it C. / D. those
2. Girls in the country are happier than ＿＿＿in the city.

A. that B. it C. / D. those

3.The school is more beautiful now than____ in the past.

A. that B. it C. / D. one
4.The school here is more beautiful than____ in that village.

A. that B. it C. / D. one

5.The weather in Shanghai is hotter than ____ in Beijing.

A. that B. it C. / D. those

5.The weather here is colder in March than____ in December.

A. that B. it C. / D. those

My goodness,which should I choose? why?

[Lost_Soul]

I'd solve it thusly:

[Vaok]

Thank you. But I need a native to confirm it.

[Pamela]

Hi vaok,
Surely, you are entitled to wait for the native speakers of our forum, but I'd like to mention that I agree with Alex's suggested options and am going to add two more left unanswered

5. a)The weather in Shanghai is hotter than that in Beijing.
b)The weather here is colder in March than in December.

[Forastero]

Could you explain this to me?

in the first and second sentence there's olny a change at the word order. Why the second sentence needs the conjunction and not the first one?

Thanks

[Vaok]

Pamela,

thank you.that's what I want. I agree with you now.

[Pamela]

You're welcome, Vaok.