public class UIModel
    {
        public int PersianYear { set; get; }

        public int[] SelectedPersianMonths { set; get; }
    }

var model = new UIModel
{
    PersianYear = 1391,
    SelectedPersianMonths = new[] { 4, 5 }
};

var itemsQuery = context.Members.AsQueryable();

// Linq chaining where clauses as an `Or` instead of `And`
var predicate = PredicateBuilder.False<Member>();

foreach (var month in model.SelectedPersianMonths)
{
    var start = new DateTime(model.PersianYear, month, 1, new PersianCalendar());
    var end = new DateTime(model.PersianYear, month, month <= 6 ? 31 : 30, new PersianCalendar());

    // We can chain `IQueryable`s.
    // itemsQuery = itemsQuery.Where(x => x.JoinDate.Date >= start && x.JoinDate.Date <= end);
    // But it will be translated as an `AND`, not `OR`

    predicate = predicate.Or(x => x.JoinDate.Date >= start && x.JoinDate.Date <= end);
}

itemsQuery = itemsQuery.Where(predicate);

var items = itemsQuery.Select(x => new { x.FirstName, x.Surname }).ToList();

SELECT [m].[FirstName],
       [m].[Surname]
FROM   [Members] AS [m]
WHERE  ((CONVERT (DATE, [m].[JoinDate]) >= '2012-06-21T00:00:00')
        AND (CONVERT (DATE, [m].[JoinDate]) <= '2012-07-21T00:00:00'))
       OR ((CONVERT (DATE, [m].[JoinDate]) >= '2012-07-22T00:00:00')
           AND (CONVERT (DATE, [m].[JoinDate]) <= '2012-08-21T00:00:00'));

PM> Find-Package DNTCaptcha

Id                                  Versions                                 Description                                                                                                                       
--                                  --------                                 -----------                                                                                                                       
DNTCaptcha.Core                     {1.6.0}                                  DNTCaptcha.Core is a captcha generator and validator for ASP.NET Core applications.                                               
Abp.AspNetCore.NRCaptcha            {1.0.0}                                  通过 DNTCaptcha.Core 进行改写的...                                                                                                       
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