What sentences are correct?<br/><br/>1. He has worked only for 2 years.<br/><br/>2. He has worked only 2 years.<br/><br/>3. He has worked for only 2 years.<br/><br/>4. He has worked for 2 years.<br/><br/>5. He has only worked for 2 years.<br/><br/>6. He has only worked 2 years.<br/><br/>7.He has worked 2 years.<br/><br/>Q