Question:
Who was the chair of International Astronomical Union in Jul, 2019?

Context:
 Ewine van Dishoeck is the chair of International Astronomical Union from Jan, 2018 to Jan, 2021. 
 Debra Elmegreen is the chair of International Astronomical Union from Jan, 2022 to Jan, 2024. 
 Robert Williams is the chair of International Astronomical Union from Jan, 2009 to Jan, 2012.

Answer:
Question:
Who was the chair of International Astronomical Union in Jul, 2019?

Context:
 Ewine van Dishoeck is the chair of International Astronomical Union from Jan, 2018 to Jan, 2021. 
 Debra Elmegreen is the chair of International Astronomical Union from Jan, 2022 to Jan, 2024. 
 Robert Williams is the chair of International Astronomical Union from Jan, 2009 to Jan, 2012.

Answer:
user
Ewine van Dishoeck
assistant
Question:
Who was the chair of International Astronomical Union in Jul, 2019?

Context:
 Ewine van Dishoeck is the chair of International Astronomical Union from Jan, 2018 to Jan, 2021. 
 Debra Elmegreen is the chair of International Astronomical Union from Jan, 2022 to Jan, 2024. 
 Robert Williams is the chair of International Astronomical Union from Jan, 2009 to Jan, 2012.

Answer:
user
Debra Elmegreen
Robert Williams
assistant
Question:
Who was the chair of International Astronomical Union in Jul, 2019?

Context:
 Ewine van Dishoeck is the chair of International Astronomical Union from Jan, 2018 to Jan, 2021. 
 Debra Elmegreen is the chair of International Astronomical Union from Jan, 2022 to Jan, 2024. 
 Robert Williams is the chair of International Astronomical Union from Jan, 2009 to Jan, 2012.

Answer:
user
Ewine van Dishoeck
assistant