11. I find it difficult to understand his accent. I have ______________________________________________________________ 12. Helen started to study French in 1995. Helen has ____________________________________________________________ 13. We should brush our teeth carefully after meals. Our _________________________________________________________________ 14. Linda is no longer late in class. She _________________________________________________________________ 15. I haven't seen her for three years. I last ________________________________________________________________ 16. She could hardly hear what he was saying. It was difficult ________________________________________________________ 17. She came to London a year ago. She has ____________________________________________________________ 18. He learned to drive when he was eighteen. He has ____________________________________________________________ 19. They made her pay $ 2000 tax. She ______________________________________________________________ 20. It was difficult for them to to this test. They had