英語中助動詞should, would的用法

助動詞：輔助其他動詞構成時態、語態、疑問句式、否定名式的動詞。助動詞有些詞義，有些沒有詞義，或者暗含一點詞義。放在謂語首位置助動詞會受主語人稱、數的限制，其他位置不會受限制。

should, would用來表示過去將來時態，should用於第一人稱，would用於第二、三人稱(在美國也可用於第一人稱)：

I said I should turn in the exercise book the next day.

我說我將在第二天交作業本。

He asked whether they would come back that evening.

他問他們是否當天晚上回來。

should和would常用於虛擬語氣中：

If it should rain tomorrow, I would stay at home.

如果明天下雨，我會待在家裏。

If he should come back, we would welcome him.

要是他回來，我們會歡迎他。

Put on your raincoat in case it should rain.

穿上雨衣，以防下雨。

should表示驚訝和“應該”：

It surprised us that he should have failed in the test.

他竟然測試沒過關，我們感到很驚訝。

Why should he have made such a big mistake?

他怎麼會犯這麼大的錯誤呢?

You should have informed me two days in advance.

你們應該提前兩天通知我。

We should learn from and help each other.

我們應該互相學習，互相幫助。

would常用於委婉、客氣地提建議、請求：

Would you help me serve tea?

你幫我上荼好嗎?

What would you like to eat?

你想吃點什麼呢?

I’d like some vanilla ice-cream.

我想要些香草冰淇淋。

would同will一樣常用於表示習慣或者傾向：

When she was free, she would go shopping.

她有空時就會逛商店。

When asked a very simple question, he would laugh it off.

當有人問他一個很簡單的問題時，他會一笑了之。