Preposition 5

 I usually stay at home _____night.

Prepositions are words that indicate relationships with the other words in the sentence. Prepositions of time are used to denote time in a sentence.

Let's look at the usage of various alternatives in the option as preposition of time:

 at : to refer to an exact time of the day, also used along with "night"

 with : to mean "at the same time"

 in : to refer to a period of time, usually years / months / seasons / morning / afternoon / evening

 over : to express the duration

Clearly, the most appropriate word here is "at".

Thus the correct compelte sentence is:

I usually stay at home AT night.