Welcome to another English grammar lesson. This one is about learning the present perfect tense from past to present, especially when using for and since. Let's say this is you. You have an idea. You want to get a job so you can make some money, maybe buy a car, travel the world, meet someone, fall in love, get married, buy a house and have two beautiful children. And then you realize your whole has life flashed before your eyes and you don't even remember what happened. Wait, what were we talking about? Right. You wanted to get a job. Which means you'll have to go to an interview where someone will ask you about your job experience, and you'll have to answer their questions about your experience, often using the present perfect tense. The interviewer might ask you, what kind of experience do you have? And you'll say, well I have worked with computers for ten years, and the interviewer will ask, great! How long have you studied English? And you'll answer, I have studied it since I was 12 years old. Now let's look more closely at your answers to the questions. Notice the verbs used in your answers, have worked, and have studied. This is the present perfect tense, and it often goes with the word for or since. The present perfect tense connects the past with the present, and often uses for with a specific amount of time, or since with the date in the past. When making present perfect tense, I, you, we, they, goes with have followed by the past participle of the main verb. He, she, it, goes with has, followed by the past participle of the main verb. Both parts are needed to make the present perfect tense. The past participle is the ED ending for regular verbs, or irregular endings for irregular verbs, such as written for write. In the sample sentence, I have worked with computers for 10 years, have goes with the subject I, and worked is the past participle of work. I have studied it since I was 12 years old. Again, we use have because of the subject I, and studied is the past participle of study. Now let's look at a few other sample sentences. Bill has grown since the last time I saw him. Bill goes with has and grown is the past participle of grow, the main verb. You have had a cold for two weeks. You goes with have and had is the past participle of have, the main verb. And it's perfectly okay to have both have and had in the same sentence using the present perfect. Notice that in each of these sentences we use for or since to describe the amount of time between the past and present. For 10 years, since I was 12 years old, since the last time I saw him, for two weeks. For is used to show the length of time, or how long something happened. For 12 hours, for 2 days, for 5 weeks, for 8 years. Since is used to show when the action started at a specific point in time in the past. Since yesterday, since last year, or last month. Since I talked to you. Since we were away. Since a month ago. Since 1999. Let's practice. Decide if we need FOR or SINCE in each of the following sentences. And that's the present perfect tense connecting the past to the present using for and since.