题目

语法填空 Do you want to have a big adventure(探险)with no big dangers? Try letterboxing. It's really (excite). Letterboxing began England in 1845. It was like hiking and exploring with a special adventure. Someone (make) a letterbox -- a small box with a little notebook in it. The person hid the letterbox in a park, a forest, a city or other (place). Next, the person would write directions(方向) to the box， put the directions on the internet. Then letter boxers used (they) to look for the letterbox. Letterboxing might not be as popular as skydiving or rock climbing, but it's a grea丝绸摩擦过的玻璃棒带_____电（选填“正”或“负”），带电玻璃棒与不带电的验电器金属球接触，金属箔片因带_____（选填“同”或“异”）种电荷相互排斥而张开。