露 and 霜: dew wetting shoes and frost beginning to melt
Compare 露 shining on grass or wetting shoes with 霜 on a field or beginning to melt on a roof. Read the cause of wetness separately from the object and stage of melting.
Shining dew and the cause of wet shoes
露（つゆ） means dew. 「朝日を受け、草の葉の露が銀色に光った。」（Dew on the grass shimmered silver in the morning sun.） 朝日を受け gives the morning-sun context. 銀色に光った describes dew on grass shining silver.
「野原を歩くうちに靴が朝露でぬれた。」（My shoes became wet with morning dew as I walked through the field.） 朝露で identifies morning dew as the cause of the shoes becoming wet. 野原を歩くうちに gives the situation of walking through the field. Preserve that cause rather than replacing it with rain or frost.
Frost on a field and melting on a roof
霜（しも） means frost. 「冷え込んだ朝、畑に白い霜が降りた。」（White frost covered the field on the cold morning.） 冷え込んだ朝 supplies the cold-morning setting, and 畑に identifies the field. 白い describes the frost in this scene.
「屋根の霜が日差しを受けて溶け始めた。」（The frost on the roof began to melt in the sunlight.） 日差しを受けて supplies the sunlight context, and 溶け始めた marks the beginning of melting. 屋根の霜 is what changes; beginning to melt does not establish complete melting or disappearance.
Description, cause, and stage
The dew example includes 銀色に光った, and the field example includes 白い霜. Each sentence names its object before describing it. Silver shine or whiteness alone does not become a universal rule for identifying every wet surface.
The shoe sentence uses 朝露で to explain why the shoes became wet. The roof sentence uses 霜が溶け始めた to describe what began changing and how. Reading the cause of wetness separately from the stage of melting distinguishes the scenes.
In 「野原を歩くうちに靴が朝露でぬれた。」 and 「屋根の霜が日差しを受けて溶け始めた。」, what made the shoes wet, and what stage of change does the frost on the roof reach?
Show the answer and why
Morning dew made the shoes wet. The frost on the roof began to melt in the sunlight. The sentences do not replace dew with rain or frost as the cause of wetness, or establish that all the roof frost disappeared.