What preposition starts with the letter r?

The pronouns that begin with the letter L are the indefinite pronouns less and little.

Examples:

We try to help those who have less than we have.

Little has been done to improve safety.

Note: When the Words 'less' and 'little' are placed before a noun to describe that noun, they are adjectives:

'Little improvement has been done...'; '...less points than we have.'