1. If you <b><u>had met</u></b> her yesterday, you <b><u>would seen</u></b> how thin she was.<br/><br/>could anybody correct this sentence for me.<br/><br/>2.Did you hear her laugh just now.<br/><br/>why can't I use laughing here<br/><br/>3.Fewer students have played truant since the new system was implemented. <br/><br/>Can I say has implemented.<br/><br/>please tell me reasons of the three question in detail and give many examples to compare. Great thanks in advance.