托福TPO是考生备考托福的必备材料。想要提高托福阅读能力，很多考生会选择托福TPO作为练习材料。而TPO阅读中常常出现长难句，解析困难，成为阅读障碍。在此，出国留学网小编为大家整理了托福TPO1-26中的阅读长难句，阅读能力较高的同学，可以借此机会测试一下自己的真实能力。
TPO1：Groundwater
1. The same thing happens to this day, though on a smaller scale, wherever asediment-laden river or stream emerges from a mountain valley onto relatively flat land,dropping its load as the current slows: the water usually spreads out fanwise, depositingthe sediment in the form of a smooth, fan-shaped slope.
2. Sediments are also dropped where a river slows on entering a lake or the sea, thedeposited sediments are on a lake floor or the seafloor at first, but will be located inlandat some future date, when the sea level falls or the land rises; such beds are sometimesthousands of meters thick.
3. In lowland country almost any spot on the ground may overlie what was once the bedof a river that has since become buried by soil; if they are now below the water’s uppersurface (the water table), the gravels and sands of the former riverbed, and its sandbars,will be saturated with groundwater.
4. This is because the gaps among the original grains are often not totally plugged withcementing chemicals; also, parts of the original grains may become dissolved bypercolating groundwater, either while consolidation is taking place or at any timeafterwards.
5. But note that porosity is not the same as permeability, which measures the ease withwhich water...