David studied for his math exam for several hours
David received the highest grade in his class.
I would rephrase like this: Receiving the highest grade in his math class, David had studied for his exam for several hours.
But this sounds wrong to me, somehow?? People could think the two thing happened all at once?
David studied for his math exam and David received the highest grade in class
After studying for his math exam for several hrs, David received the highest grade.
Now, which one of these 3 sentences separates the two things by the right amount of time?