Let us look at one of the error types that are frequently tested on SAT writing
Due to / because of
the class has been cancelled due to rain
this sentence looks correct but SAT does't accept it , because 'due to' can't modify verb cancel . when there is a main verb in the sentence , it should always go with 'because of 'or because . so, right answer is : the class has been cancelled because of rain
Similarly , when there is noun in the sentence , because of or because can not be used .look at this example
my top score is because of my teacher
in this sentence , there is no main verb . So we must use only' due to '
So, the correct answer will read : my top score is due to my teacher