Why was 'nous sommes apparues' marked incorrect?

Question

The lesson says:Conjugations of APPARAÎTRE (to appear) in Le Passé
Composé (Indicatif) in French

j'/je

suis apparu(e)

tu

es apparu(e)

il / elle / on

est apparu(e)(s)

nous

sommes apparu(e)s

Accepted Answer

Hi Jenny-Anne,
If you mean the quiz question -
How would you say "Then we appeared on the screen" 
The correct answer was -
 Both sentences are correct 
as you can say
Puis, nous sommes apparus 
and 
Puis nous avons apparu
Hope this answers your query.

Answer

Bonjour Jenny-Anne,I suspect that you have not included the auxiliary (avoir) version."French verb apparaître is very unusual in Le Passé Composé (Indicatif), in that it can take either avoir or être as its auxiliary."Otherwise, I cannot fault what you have written for nous sommes apparu(e)sBonne journéeJim