| 1. | Land must be well drained for some crops .
某些作物要求土地有良好的排水性能。 |
| 2. | Drainage usually has to be undertaken as a first operation .
第一步通常采取排水措施。 |
| 3. | Sewerage systems are either "separate" or "combined" .
排水系统有“分流制”和“合流制”。 |
| 4. | A layer of coarse gravel is often placed around the drain tile .
常常在排水瓦管周围铺一层粗石砾。 |
| 5. | Poor drainage causes deficient soil aeration and death of the roots .
排水不良能减低土壤的透气性，使根死亡。 |
| 6. | In the united states, central wisconsin has the well-drained soil .
美国威斯康星州中部有着排水情况良好的土壤。 |
| 7. | Dick was patiently explaining about soils and drains and native wages .
迪克耐心地解释土壤、排水和工人工资等事情。 |
| 8. | Drainage was to the north and individual channels bifurcate in that direction .
整个水系向北排水，各个河道朝该方向分叉。 |
| 9. | The resulting effluent is then diluted upon combination with the total plant effluent .
所得的排出水与全厂排水汇合而被稀释。 |
| 10. | After twenty-four hours free drainage, there was little difference in moisture content .
24小时不排水，湿度则几乎没什么不同。 |
