German phrase
Welche Gründe führen zu ~?
Meaning
What causes ___?
When to use it
It asks about causes. It is polite and general.
Example dialogue
Welche Gründe führen zuHeimweh?
What causes homesickness?
Daran sind meist Einsamkeit und Sprachprobleme schuld.
Loneliness and language problems are usually to blame.