dissolve 与 melt 两词都指由固体转变为液态。

 (1) dissolve指固体因水而溶解，如盐、糖等；可作及物动词，也可作不及物动词。

• Dissolve the tablet in a glass of water before taking it.
  将药片溶解到一杯水里再服用。
• Salt and sugar dissolve in water.
  盐和糖可溶于水。

 (2) melt指固体因热而融化，如雪、冰淇淋、奶油等，也指金属受热“熔化”。

• The snow was melted by the spring sun.
  春天的太阳融化了积雪。
• The ice cream began to melt when it was brought to her room.
  冰淇淋送到她房间里时就开始融化了。
• Lead melts at a lower temperature than iron, as lead has a lower melting-point than iron.
  铅熔化的温度比铁低，因为铅的熔点比铁低 。