Bonjour,
Réponse :
a. the / sleeping / cat / Is /?
Is the cat sleeping?
b. are / dogs / bark / The / they / when /scared.
The dogs bark when they are scared.
c.is/is / The / baby / because / he / hungry/ crying.
The baby is crying because he is hungry.
d. are / What / children / the / doing /?
What are the children doing?
;)