Why can it instead ??

英文文法和用法，確是有很多是要死記，但並不等是完全沒得解釋的。

其實 "too ...... to ...... " 這個英文用法，是 inversion； 將一件事放在 "to" 後面，另將一個形容詞放在 "too" 後面 ，去解釋相反於第一件事的效果。

例如： we are too [excited] to [sit still]: [sit still 安坐] 是一件事，[excited 興奮] 是形容詞。 整句= 我們不能安坐，因為我們太過興奮。

We were too excited to sit still 我們興奮到不能安坐。
= We could not sit still because we were too excited 由於我們太興奮，所以不能安坐。
= We were so excited that we could not sit still 我們興奮到不能安坐。

其它例子：
It sounds too good to be true = It is not true becasue it sounds too good.= It sounds so good that it can not be true.

She is too young to drink = She should not drink because she is too young = She is so young that she should not drink.

你試想 We were too full to eat more.= 我們太飽難以再多吃。
那麽 We were too excited to sit still.= 我們太興奮難以安坐。

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應該係個too字影響吧

We were too excited to sit still. ~ 我們過分興奮至難以安坐的地步/ (心情超越能只是坐着。)

We were so excited that we could not sit still. (Relative Clause)~ 我們十分興奮。我們無法安坐。

第一句 :這是英文的句法，難以中文解釋，多看點有這些句式的文章，讀多幾篇則能撐握其意思及用法！