Mimic SQL IN Clause with LINQ [duplicate]

I am trying to mimic an IN() clause commonly used in SQL and use it in my LINQ statement. I see that there is an overload for Contains() that takes an IEnumerable collection. I have tried passing in ILIST and Dictionary but neither is correct. How do I accomplish this?

Thanks, much appreciated.

SQL

select oec.OnlineEducationCourseId, oec.CourseTitle,COUNT(oec.CourseTitle) as CourseCount from OnlineEducationRegistration as oer join OnlineEducationCourse oec on oec.OnlineEducationCourseId = oer.OnlineEducationCourseId where oer.ClubId IN('K20','B67','P89') and DateCompleted between '2013-01-01' and '2014-01-01' group by oec.CourseTitle,oec.OnlineEducationCourseId 

Same SQL query in LINQ

var r = (from oer in db.OnlineEducationRegistrations join oec in db.OnlineEducationCourses on oer.OnlineEducationCourseId equals oec.OnlineEducationCourseId where (oer.ClubId.Contains(some IEnumerable collection here) && oer.DateCompleted >= start.Date && oer.DateCompleted <= end.Date) group new { oec, oer } by new { oec.CourseTitle, oec.OnlineEducationCourseId }).ToList();