Ladis and gntlmn, I want to say somthing about trs. As w know now trs ar vry important to human bings. First of all, thy bnfit our halth. Thy snd out oxygn for us to brath. W can't liv without trs.Scondly, trs can bautify our nvironmnt. As trs ar so important, w must do our bst to protct thm. W must nforc th tr protction laws. W must plant as many trs as possibl.Only in this way can w liv happily in th bautiful world.