【Do第三人称单数】在英语语法中,“do”是一个非常常见的助动词,用于构成疑问句和否定句。然而,在第三人称单数(如he, she, it)的情况下,"do"需要进行形式上的变化,变成“does”。这是英语语法中一个重要的知识点,尤其对于初学者来说容易混淆。
“Do”在一般现在时中,用于第一人称(I, we)、第二人称(you)和复数第三人称(they)的句子中。当主语是第三人称单数(he, she, it)时,必须使用“does”来构成疑问句或否定句。这种变化不仅适用于动词原形,还会影响整个句子的结构。
例如:
- 肯定句:He does his homework every day.
- 疑问句:Does he do his homework every day?
- 否定句:He does not do his homework every day.
掌握这一规则有助于正确构建句子,避免语法错误。
表格对比:
主语 | 肯定句结构 | 疑问句结构 | 否定句结构 |
I | I do... | Do I...? | I do not/do not... |
You | You do... | Do you...? | You do not/do not... |
We | We do... | Do we...? | We do not/do not... |
They | They do... | Do they...? | They do not/do not... |
He/She/It | He/She/It does... | Does he/she/it...? | He/She/It does not... |
通过以上表格可以看出,除了第三人称单数外,其他主语都使用“do”,而“does”仅用于he、she、it。这一规则虽然简单,但在实际应用中非常重要,特别是在口语和写作中保持语法正确性。