What is let alone?

"Let alone" is an English idiomatic phrase used to emphasize a contrast between two statements, where the second one presents a scenario that is even more extreme or unlikely than the first. It's typically used to highlight that if something is true or likely in one situation, it is even more so in another.

For example, in the sentence "He can't boil water, let alone cook a full meal," the phrase indicates that boiling water is a simpler task compared to cooking a full meal. If the person cannot perform the simpler task, he is even less likely to be able to perform the more complex one.

Here are a few key points about the use of "let alone":

1. Contrast and Emphasis: It emphasizes the difficulty or improbability of the second scenario compared to the first.

2. Structure: Generally follows a statement to introduce a more emphasized contrasting point.

3. Negative Context: It often appears in contexts where the initial statement is negative or poses a limitation, thereby underscoring the greater impossibility of the second condition.

4. Common Usage: "Let alone" is commonly used in everyday English for both formal and informal communications.

In summary, "let alone" is a rhetorical tool to stress a point about conditions or actions that are progressively more unlikely or difficult.