Every once in awhile, one fails to complete their homework in time. To get away with it, you need a proper excuse that will be convincing enough to your teacher. While some teachers may be more gullible than others, here are some of the excuses you could use.
It is possible that your backpack can be stolen on the day the assignment is due. Trying to trace who stole your backpack or how true that is could be too much work for the teacher. This could help you get away with it.
You could say you fell ill and were unable to complete any of the tasks given. While some teachers could demand a medical report indicating so, most teachers will not follow through. However if you always use this excuse, you could get caught some day.
This could be a good idea since it is highly unlikely the teacher could expect your Dad to leave work in order to bring your assignment to school
For ladies you can easily get away by saying it's that time of the month. If you are a boy and you decide to say this, trust me you will be in bigger problems than not completing homework.
You could say one of your relative, like Grandpa just died. Well any right thing teacher would not debate about that. However, using this excuse too many times will also get you caught too.
If this was a typed assignment, you could say your computer crashed. Everybody including your teacher knows these stuff happens every now and then so it won't look odd.
While it is a good option to lie about it, sometimes just saying the plain truth could get you off the hook. Tell the teacher what exactly happened. Some teachers will actually understand that you didn't choose to use homework doers to pass in your assignment and were honest about that.