Write a letter to a friend in another school telling him/her your anticipation for next academic term
and your new class

Mary decided to stay home from work, she was just so tired from last night's party

Explanation:

Ideally for the sentence shown in the question above is to separate the two statements by comma. This would make the sentence more cohesive, pleasant to read and more coherent.

The comma is a punctuation mark that serves to separate the elements of a sentence or to indicate a pause. In addition, the sentence shown in the question represents a sentence made up of two coordinated sentences. When two coordinate sentences are together without the conjunction "and", as is the case with the above sentence, a comma should be used to separate them.

In this case, the correct sentence would be:  "Mary decided to stay home from work, she was just so tired from last night's party ."