“是……的”句：强调施事者 The Structure "是……的": emphasizing the agent of an action

在已经知道事情发生的情况下，可以用“是……的”强调动作的发出者。例如：
When the occurrence of an action is known, "是……的" can be used to emphasize the agent of the action. For example:

否定形式在“是”的前边加“不”。例如：
In the negative form, "不" is added before "是". For example:

在已经知道事情发生的情况下，可以用“是……的”强调事情发生的时间、地点、方式等。肯定句和疑问句中的“是”字可以省略，否定句中不能省略。
When the occurrence of something is known, "是……的" can be used to emphasize when, where and in which manner it occurred. "是" can be omitted in positive and interrogative sentences, but not in negative sentences.

否定形式：
The negative form: