Can you explain the difference using the example of "She has written a book" vs. "She has been writing a book"?

In information theory, the entropy of a random variable quantifies the average level of uncertainty or information associated with the variable's potential ... Sep 26, 2017 ... ... present perfect tenses. Both of these words explain how long something has been happening. So, when you want to give more information about ... Auctions. Extensive form games of incomplete information. Perfect Bayesian (Nash) Equilibria. Introduction to social learning and herding. The Present Perfect Continuous tense uses two auxiliary verbs together with a main verb. In this lesson we look at the structure and use of the Present Perfect ... Present (simple). I send; you send; he sends; we send; you send; they send. Present progressive / continuous. I am sending; you are sending; he is sending ... Jun 2, 2010 ... Distinguish between information ... and publish writing and present the relationships between information and ideas clearly and efficiently. Talking about experiences using Present Perfect and Past Simple. General Grammar. In the first lesson, students learn the differences between the two tenses and ... Mar 17, 2021 ... No. What is true is that Americans sometimes use the simple past tense in contexts where British speakers would use the present perfect. In other verb tenses – present continuous, present perfect, etc. – the ... When you are going to ask a question in the simple present or simple past using who or ... May 20, 2021 ... In this article, we define and break down the usage of the present perfect continuous tense. For information and resources on all verb ...