1.l can't finish this task if you don't give me a hand.

=> Unless you give me a hand, I can't finish this task.

2.You will run out of money if you don't stop wasting it.

=> Unless you stop wasting money, you will run out of it.

3.Don't call me unless it is an emergency.

=> If it is not an emergency, don't call me.

4.James will not pass the test unless he studies harder.

=> If Jame doesn't study harder, he will not pass the test.

5.If Jane finishes her work before 6 pm, she will dine out with her friends.

=> Unless Jane finishes her work before 6 pm, she will not dine out with her friends.