How to read 4,444,444 in English?

They arrived ______ a cold morning in winter. [ ]

The boy ___________ exercises, so he has to see the doctor because of overweight.

Shanghai is larger than __________ city in China. – Yes. And it is larger than __________ city in Jiangsu.

Carl, why not go and help your sister water the flowers there? —Why__________? I’m busy myself. Jack is lying on the grass doing nothing.