 And now we'll have a look at the present perfect continuous tense. As its name suggests, what we're going to do is combine the present continuous usages and the present perfect usages into a tense that basically expresses the fact that we've got an action continuing up until the present point in time. For the form of this tense, again we're going to combine the various aspects of both the perfect and the continuous tenses. If we have a look, we always begin with our subjects. Then we have our two now helping verbs. The helping verb to have for the perfect tenses, as well as the helping verb be for the continuous tenses. For our subjects I, you, we, and they, we leave have as have. For he, she, and it, we conjugate it to has. Because it's a continuous tense, of course we need to use the verb plus ing. This results in sentences such as I have been teaching quite some time or she has been teaching for 15 years. The negative form of the present perfect continuous remains the same as the positive form and we simply add not in between our two helping verbs have and be. In order to make the present perfect continuous questions, again following with that pattern of inversion, what we've done is put the auxiliary verb have at the beginning of the sentence followed now by the subject. Have I been teaching for five years, could be a sentence used there, and again we're going to conjugate our verb to has for he, she, it, resulting in has she been teaching for five years. The usages for the present perfect continuous tense are very similar to that of the present perfect tense. But here the focus is on the action and the fact that it has been continuing for some time leading up to the present. Let's have a look. We've got incomplete and ongoing activities with duration. I have been teaching for 10 years. Then we have our recently finished activities with present results. Our recently finished activity is chopping trees, but the present result is he is tired. So results in a sentence reading he is tired because he's been chopping trees.