udapi
diff --git a/‎udapi/block/tutorial/__init__.py‎ b/‎udapi/block/tutorial/__init__.py‎
diff --git a/‎udapi/block/tutorial/adpositions.py‎
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+"""tutorial.Adpositions block template.
+
+Example usage:
+for a in */sample.conllu; do
+    printf '%50s ' $a;
+    udapy tutorial.Adpositions < $a;
+done | tee results.txt
+
+# What are the English postpositions?
+cat UD_English/sample.conllu | udapy -TM util.Mark \
+ node='node.upos == "ADP" and node.parent.precedes(node)' | less -R
+"""
+from udapi.core.block import Block
+
+class Adpositions(Block):
+    """Compute the number of prepositions and postpositions."""
+
+    def __init__(self, **kwargs):
+        """Create the Adpositions block object."""
+        super().__init__(**kwargs)
+        self.prepositions = 0
+        self.postpositions = 0
+
+    def process_node(self, node):
+        # TODO: Your task: distinguish prepositions and postpositions
+        if node.upos == "ADP":
+            self.prepositions += 1
+
+    def process_end(self):
+        total = self.prepositions + self.postpositions or 1
+        prep = 100 * self.prepositions / total
+        post = 100 * self.postpositions / total
+        print("prepositions %5.1f%%, postpositions %5.1f%%" % (prep, post))