26. A. outside: The traffic light was installed outside the House of Parliament. This indicates the location.
27. A. resembled: The traffic light resembled a railway signal. "Resembled" means to look like something else.
28. A. However: However, it exploded. This shows a contrast between the initial installation and the unfortunate event.
29. C. discouraged: The accident discouraged further development. The accident made people less enthusiastic about developing the technology.
30. A. New: New traffic lights are an American invention. This refers to a different type of traffic light.
31. B. systems: Red-green systems were installed. "Systems" refers to a set of connected parts forming a complex whole.
32. B. operated: Three-color signals were operated by hand. "Operated" means controlled or worked
33. D. middle: From a tower in the middle of the street. This indicates the central location of the tower.
34. C. first: The first lights of this type. This indicates the initial appearance of this kind of traffic light in Britain.
35. B. appear: To appear in Britain. "Appear" means to become visible or present.