ExampleQueries.cs

// Pagination as a function
static IQueryable<T> Paginate<T>(this IQueryable<T> query, int pageNumber, int pageSize) =>
    query.Skip(pageSize*pageNumber).Take(pageSize);

// Usage
var paginatedQuery = originalQuery.Paginate(pageNumber, pageSize);

// Composition (fluent with extension methods)
var paginatedFilteredQuery = originalQuery.Where(predicate).Paginate(pageNumber, pageSize);

// Composition (classical)
var filteredQuery = Where(originalQuery, predicate);
var paginatedFilteredQuery = Paginate(filteredQuery, pageNumber, pageSize);

// Pagination as a decorator
class PaginatedQuery<T> : IQueryable<T>
{
    private readonly IQueryable<T> query;
    
    public PaginatedQuery(IQueryable<T> query, int pageNumber, int pageSize)
    {
        // Basically the same as Paginate function, that's why I prefer the function
        this.query = query.Skip(pageSize*pageNumber).Take(pageSize);
    }
    
    #region IQueryable<T> implementation...
    public Type ElementType => query.ElementType;
    public Expression Expression => query.Expression;
    public IQueryProvider Provider => query.Provider;
    public IEnumerator<T> GetEnumerator() => query.GetEnumerator();
    #endregion
}

// Usage
var paginatedQuery = new PaginatedQuery(originalQuery, pageNumber, pageSize);

// Composition
var filteredQuery = new FilteredQuery(originalQuery, predicate);
var paginatedFilteredQuery = new PaginatedQuery(filteredQuery, pageNumber, pageSize);

// Combination - ridiculous in this case but that's how Skip, Take, Where and other combinators are often defined.
static IQueryable<T> Paginate<T>(this IQueryable<T> query, int pageNumber, int pageSize) =>
    new PaginatedQuery(query, pageNumber, pageSize);