【每日听力 • 真题系列】
The company spent the last five years 1 that are only about a quarter of an inch thick and are 2 without breaking or 3 . The panels are also designed so that they can be installed directly on top of existing roadways, 4 . France isn't the first country to 5 with solar panels.
【出处:2017年12月四级听力第一套,报告2】