Is this sentence correct?
You have to put some serious effort in on this.
or is this one correct?
You have to put some serious effort in this
If you want to say put effort, should you use 'in' all the time or does it depend? If it is latter, how?
You have to put some serious effort in on this.
or is this one correct?
You have to put some serious effort in this
If you want to say put effort, should you use 'in' all the time or does it depend? If it is latter, how?