苏州市2014
高考英语阅读理解、完形填空及阅读类训练（3）（答案及解析） words：318 难度系数：★★★ 建议用时：9分钟 the treadle pump is based on a design developed in the 1970s by norwegian engineer gunnar barnes.it can be made locally. the treadle pump is easy to build from bamboo or other wood and has two metal cylinders (圆筒) with pistons (活塞)．the pistons go up and down as a person stands on lever devices—treadles，and
