I have made some sentences in my workbook but I'm not sure if it's right or wrong.<br/><br/>I expect you to help me find the answers.<br/><br/>1. Joe changed his major from French to bussiness with the hope for being able to find a better job.<br/><br/>2. According to my estimates, we should have enough money for the rest of the month.<br/><br/>3. I'm very tired now. I have driven/have been driving over 200 miles today.<br/><br/>4. Some interesting questionnaires have been done in libraries.<br/><br/>5. While alpine flowers which can resist wind, cold and snow, their small size and the thin soil make them easy prey to a hiker's heel.<br/><br/>6. One's fingerprints are different from those of any other person.<br/><br/>7. Bicycles are both silent and clean, and also are easy to park.<br/><br/>8. Although solar energy is cheaper than oil, both of which have advantages as well as disadvantages. <br/><br/>Thanks a lot.