The combination of “not” and ”all” can be confusing if you’re not careful about placement. “All politicians are not corrupt” could theoretically mean that no politician is corrupt, but what you probably mean to say is “Not all politicians are corrupt.” When “not all is a minority, it’s sometimes better to replace “not all” with “some.&rdquo “The widescreen version is not available in all video stores” can be made clearer by saying “The widescreen version is not available in some stores.”