Need

 Here's a chart that shows the different uses of the verb "need," along with the phrases "didn't need to" and "needn't have":

Form	Meaning	Example
Need (modal verb)	Necessity or obligation	I need to finish this project by tomorrow.
Need (ordinary verb)	Necessity or requirement	The car needs new tires.
Didn't need to	Not necessary or required	You didn't need to buy a gift for me.
Needn't have	Unnecessary or not required	You needn't have stayed up so late to finish that report.

Here's a brief explanation of each form:

1. Need (modal verb): When used as a modal verb, "need" expresses necessity or obligation, and is followed by a base verb. For example, "I need to finish this project" expresses the speaker's necessity to complete the project.

2. Need (ordinary verb): When used as an ordinary verb, "need" expresses necessity or requirement, and is often followed by an object. For example, "The car needs new tires" expresses the requirement for new tires on the car.

3. Didn't need to: This phrase is used to express that something was not necessary or required in the past. For example, "You didn't need to buy a gift for me" expresses that the speaker did not require a gift.

4. Needn't have: This phrase is used to express that something was unnecessary or not required in the past, despite having been done. For example, "You needn't have stayed up so late to finish that report" expresses that staying up late was unnecessary.

It's important to note that "need" is not always used as a modal verb in English, and can also function as an ordinary verb. In addition, the phrases "didn't need to" and "needn't have" are used to describe events in the past, and are not commonly used in present or future contexts.