Question

At in on? If is necessary choose the correct prepostition

i go to sleep night.
i completed my work tho hours.
i Will see you the morning.
We wear warm clothes winter.

Answer 1

I go sleep AT night.
I completed my work AT two hours.
I will sse You IN the morning.
We wear warm clothes IN Winter.

Answer 2

I go to sleep at night.
I completed my work for two hours.
I will see you in the morning. 
We wear warm clothes in winter.