diff --git a/ming/base.py b/ming/base.py
index de3073f..0d17040 100644
--- a/ming/base.py
+++ b/ming/base.py
@@ -4,6 +4,8 @@
 import warnings
 from collections import defaultdict
 from datetime import datetime
+# from typing import Iterable, Sequence
+from collections.abc import Sequence
 
 import bson
 from bson import Decimal128
@@ -74,7 +76,7 @@ def __init__(self, cls, cursor, allow_extra=True, strip_extra=True, find_spec=No
         self.cursor = cursor
         self._allow_extra = allow_extra
         self._strip_extra = strip_extra
-        self.find_spec = find_spec
+        self.find_spec = find_spec or {}
 
     def __iter__(self):
         return self
@@ -96,10 +98,12 @@ def distinct(self, *args, **kwargs):
         return self.cursor.distinct(*args, **kwargs)
 
     def limit(self, limit):
+        self.find_spec['limit'] = limit
         self.cursor = self.cursor.limit(limit)
         return self
 
     def skip(self, skip):
+        self.find_spec['skip'] = skip
         self.cursor = self.cursor.skip(skip)
         return self
 
@@ -108,6 +112,12 @@ def hint(self, index_or_name):
         return self
 
     def sort(self, *args, **kwargs):
+        if args:
+            if isinstance(args[0], list):
+                sort = args[0]
+            else:
+                sort = args
+            self.find_spec['sort'] = sort
         self.cursor = self.cursor.sort(*args, **kwargs)
         return self