As Tiffany said, it really depends on how much each assignment is worth in the class as well as how well you did on other graded assignments. In the event that you do have a lot of unfinished work affecting your grade, it never hurts to reach out to the teacher/professor to see if they will accept late assignments or offer you an extra credit assignment. Teachers are sometimes willing to offer extensions on assignments so that you can turn them in later! For the most part, whenever you're concerned about your grade, your teacher is there for you!
It really depends on the professor and their expectations. In college, you should be given an outline at the beginning of the semester that lets you know the value and weight of each assignment. Some professors will even drop the lowest grade, so you could get an A without completing all the work.
My best advice for you is to make sure you understand how you will be graded. If it is not clear, meet with the professor to gain a clear understanding. Also, try your best to complete all of your assignments.
If they DO decide weight assignments/homework heavily (each assignment is 20%), then you are unlikely to get an A.
I hope that made sense!