When you have studied this session, you should be able to:
- Define and use correctly all of the key words printed in bold.
- Describe the different types of water pollutants.
- Explain the possible ways in which water can be polluted.
- Describe measures that can be adopted for protecting water sources from pollution.
آخر تعديل: الثلاثاء, 2 أغسطس 2016, 1:47