Ⅰ.语法填空
Before discovering electricity, people relied on fire as a source of light. It was a troublesome business because fires can lead 1.________ disasters. Making fire dependable was so difficult that lights on moving vehicles were hardly ever 2.________ (consider).
The early trains 3.________ (travel) only during the day. The tracks were too dangerous during dark nights, and 4.________ (passenger) also wanted to see where they were traveling anyway. In the late 1830s, railroad traffic became so heavy that freight trains (货运火车) had to put off passenger trains. To 5.________ (avoid) these putoffs, railroads started running freight trains at night. Horatio Allen's 1831 6.________ (invent), the “Track illuminator (照明器)”， was suddenly in demand. It was a pile of special wood 7.________ (burn) in an iron grate (炉箅) that sat in a box of sand on a platform car, which was pushed ahead of the train. The illuminator did not cast much light, 8.________ it warned of an approaching train.
In 1851, the first electric headlamp was 9.________ (develop). Russia ran the first train 10.________ was equipped with a batterypowered one.
