<p>1. They have been living in Madrid <strong>since</strong> 1972.</p>
<p>2. He has been in prison <strong>for</strong> four years.</p>
<p>3. He has known about the fact <strong>for</strong> a long time.</p>
<p>4. Conditions have changed a lot <strong>since</strong> we were children.</p>
<p>5. Our teacher has been very ill <strong>since</strong> the last month.</p>
<p>6. I haven't eaten anything <strong>for</strong> twenty-four hours.</p>
<p>7. In fact he is always very rude. We have been waiting for him <strong>for</strong> half an hour.</p>
<p>8. I haven't seen him for three years. It is because I haven't been there <strong>since</strong> I left school.</p>
<p>9. I have been trying to mend this old fashioned car <strong>for</strong> hours.</p>
<p>10. One of my friends has been teaching in Tokyo <strong>for</strong> three years. I haven't met him since last year.</p>
<p>11. I haven't enjoyed myself <strong>for</strong> two weeks since I heard that my final exam grades were low.</p>
<p>12. I know that you have never seen a lion <strong>since</strong> you were born. Then now I say that we can go to the zoo and see one.</p>
<p>13. The police have been looking for him for two weeks <strong>since</strong> he escaped from the prison.</p>
<p>14. He hasn't spoken to me even a word <strong>since</strong> the last meeting.</p>
<p>15. I haven't phoned him <strong>for</strong> a week.</p>
<p>16. He has been the principal of our high school <strong>since</strong> 1988.</p>
<p>17. Dean has been learning Japanese <strong>for</strong> two years.</p>