如何在Ruby中对此字符串进行标记？

str = "Hello, #{name}!"

name = "Alice"
str = "Hello, #{name}!"
puts str

Hello, Alice!

name = "Alice"
age = 20
str = "My name is #{name}, and I am #{age} years old."
puts str

My name is Alice, and I am 20 years old.

str = "The result of " + method_name + " is " + result.to_s