Which are correct:
1-I have an assignment to write a better program for this computer.
2-I have an assignment writing a better program for this computer.
3-I have an assignment, to write a better program for this computer.
4-I have an assignment, writing a better program for this computer.
(The part after the comma could have been added as an afterthought. But I think these sentences could be used to emphasize two things equally.)
5-The thug had a contract on me to break my kneecaps.
6-The hitman had a contract on me breaking my kneecaps.
7-The thug had a contract on me, to break my kneecaps.
8-The hitman had a contract on me, breaking my kneecaps.
1
3 or 4
5
7
Note that a hitman is hired to KILL you, not hurt you. A contract is to also to kill you.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.