Without experiencing the beauty of a rainy day, one cannot describe it. (Complex sentence)

How pleasant a rainy day is! (Assertive sentence) = A rainy day is very pleasant.

It creates a very calm and refreshing atmosphere. (Exclamatory sentence) = What a calm and refreshing atmosphere it creates!

It rejuvenates nature and pleases the soul. (Interrogative sentence) = Doesn't it rejuvenate nature and please the soul?

People of all ages enjoy a rainy day. (Interrogative sentence) = Don't people of all ages enjoy a rainy day?

Little boys and girls play in the rain and enjoy themselves. (Simple sentence) = Playing in the rain, little boys and girls enjoy themselves.

We know that poets of all ages have described the beauty of rainy day. (Compound sentence) = Poets of all ages have described the beauty of rainy day and we know it.