如何动态组合linq查询？

我想一个

UNIOn

IQueryable<Sometable> baseQuery = dc.Sometable;IQueryable<Sometable> query = new List<Sometable>().AsQueryable();foreach (string l in list){    string s = l;    query.Union(baseQuery.Where(b => b.Value.StartsWith(s + separator) ||       b.Value.EndsWith(separator + s) ||       b.Value.Contains(separator + s + separator) ||       b.Value.Equals(s)));}if (query.Any()) {}