Examines a group of verbs (live, work, study, teach, speak) for which the present perfect simple and continuous are largely interchangeable. Corrects the common textbook rule that the simple form implies completion or cessation.
Explains why both ‘it hasn’t rained for a week’ and ‘it hasn’t been raining for a week’ are grammatically correct, and why negative forms of the present perfect do not always mirror their positive counterparts.