如何在neo4j中保存变量avg_time？以在另一个查询中返回它。

WITH '
  MATCH (a:authors{name:"Lui Lis"})-[:`WROTE`]->(b:papers)-[:`REFERS_TO`]->(c:fieldsofstudy)
  RETURN c.name AS field_of_study, count(b) AS number_of_papers
' AS query
UNWIND RANGE(0, 4) AS i
WITH i, query, datetime.realtime().epochMillis AS start
CALL apoc.cypher.doIt(query, NULL) YIELD value
WITH i, MAX(datetime.realtime().epochMillis-start) AS execTime
WITH COLLECT({x: execTime, y: i}) AS per_query_times, AVG(execTime) AS avg_time
UNWIND per_query_times AS z
RETURN z.x AS x, z.y AS y, avg_time

因为在这段代码中，它返回avg_time 5次，而我只想要一次。我知道我可以只返回per_query_times和avg_time而不展开任何内容，但它不适合我