diff --git a/stl/ast.py b/stl/ast.py
index 66d50fc..08ce551 100644
--- a/stl/ast.py
+++ b/stl/ast.py
@@ -30,9 +30,9 @@ class AST(object):
 
 
 
-class AtomicPred(namedtuple("AP", ["id"]), AST):
+class AtomicPred(namedtuple("AP", ["id", "time"]), AST):
     def __repr__(self):
-        return "{}".format(self.id)
+        return f"{self.id}[{self.time}]"
 
     def children(self):
         return []
diff --git a/stl/parser.py b/stl/parser.py
index 37370ba..03490b5 100644
--- a/stl/parser.py
+++ b/stl/parser.py
@@ -157,7 +157,7 @@ class STLVisitor(NodeVisitor):
         return Number(1) if node.text == "+" else Number(-1)
 
     def visit_AP(self, node, _):
-        return ast.AtomicPred(node.text)
+        return ast.AtomicPred(node.text, ast.t_sym)
 
     def visit_neg(self, _, children):
         return ast.Neg(children[1])