Noun:

1. any of various water-soluble compounds capable of turning litmus blue and reacting with an acid to form a salt and water;

   "bases include oxides and hydroxides of metals and ammonia"
   

2. a mixture of soluble salts found in arid soils and some bodies of water; detrimental to agriculture

basen.底部；基地；基础；基数；基线；(棒球)垒；[化]碱vt.以 ... 作基础adj.卑鄙的；不道德的

1. This kind of soil contains much alkali.
   这种土壤含碱丰富。
2. The key problem is to overcome alkali in the soil.
   关键在于控制土壤里的碱分。
3. Acid and alkali are the basic concept of chemistry.
   酸和碱是化学的基本概念。
4. Such detergents do not yellow the wool as alkali tends to do.
   这种洗涤剂不会象碱那样使羊毛发黄。