(1) The court should not have permitted the prosecuting attorney in his opening statement to the jury to tell it that appellant had sexual relations with prosecutrix at times before and after that charged and for which he was being tried. State v. Brown, 247 Mo. 715, 153 S.W. 1027; State v. Davis, 190 S.W. 297, 52 C.J. 1196-97; State v. Schenk, 238 Mo. 429, 142 S.W. 263; State v. Miller, 263 Mo. 326, 172 S.W. 385; State v. Caldwell, 311 Mo. 534, 278 S.W. 700. (2) The state should not have been permitted to introduce incompetent and irrelevant matters in evidence, prejudicial to the rights of appellant. State v. Teeter, 239 Mo. 475, 144 S.W. l.c. 448; Constitution of Missouri, Sec. 18 (a) Art. 1; State v. Phillips, 233 Mo. 229, 135 S.W. 4. (3) "It is the duty of the prosecuting attorney to be fair and impartial in presenting the evidence for the prosecution".