when i ?ask why the sentence use rather..than.. ?I can't explain ?exactly. ?

Mexico’s President Canceled His Meeting With Trump Rather Than Pay For The Wall

一.why 能引導(dǎo)下列幾種從句

1.主語(yǔ)從句 ? ? Why he took Chinese nationality ?in 1901 is a question that interests us.

Why he love the girl deeply?

2.賓語(yǔ)從句

He asked her why she was doing that.

3.表語(yǔ)從句

that's why I fall in love with you.

4.狀語(yǔ)從句

No matter why she became angry with you, you should ?apologise ?to her.

二， why 作疑問(wèn)詞 用來(lái)向?qū)Ψ絾?wèn)及原因

你我他的提問(wèn)

A：why are you going to do tomorrow?

why hasn't he brought ?the whisky?

why don't you look where you are going?

why can't I remember the exact year we married?

物：

why the clothes are dirty?

PS :http://gaokao.xdf.cn/201109/878805.html

Still confused. ?