correct:
b) Are they cleaning the windows?
c) Why are you laughing?
incorrect:
a) Does she collecting walnuts now?-
Is she collecting walnuts now?
d) What is he doing every day?
What does he do every day?
correct:
b) Are they cleaning the windows?
c) Why are you laughing?
incorrect:
a) Does she collecting walnuts now?-
Is she collecting walnuts now?
d) What is he doing every day?
What does he do every day?