You mustn't use a mobile on the plane 改为祈使句

You mustn't use a mobile on the plane 改为祈使句
______　________ a mobile on the plane
Does your brother often fly kites in the park?变成肯定的陈述句
Your brother often ______ ______in the park
I‘d like some orange juice to drink 改为一般疑问句
______ you like ______ oramge juice to drink?