1, If we recycled, we will save natural resources
2,If you don't be careful, you will be fall over rocks
3,If you work too much, you will feel tired
4,If you are careless, you will broke the vase
5,If Ha has work to hard, she can pass the exam
b)
1,If I knew the answer, I could give you
2,If you chose that job, you would pay for it
3, If Mrs Green had money, she could afford the house
4,If you had a pen, you could written down the address
5,If she was a president, she would change the law
c)
1, If If Jerry had understood the lesson, he would have answered
2,If Carol hadn't studied, she would have answered
3,If he had worked hard, he wouldn't have been fired
4,If I had been stucked in the traffic jam, I wouldn't have been late
5,If he hadn't gone out in the rain last night, he wouldn't have had a flu