A child's acceptance of death and eventual acquiescence to a new step-parent probably rates as one of the top ten overworked juvenile story lines. Yet Bess Kaplan sticks so close to her nine-going-on-ten-year-old heroine that this long, leisurely first-person novel is always fresh and agreeably idiosyncratic. After Mama's death during childbirth a gaggle of interfering female relatives play matchmaker to find a new Mrs. Devine for Papa, a struggling Jewish immigrant shop-keeper, and the ""poor kinder""--Becky and her pragmatic younger brother Saul. The winning ""candidate,"" hand-picked by Auntie Leah, is Miss Cohen, a schoolteacher ""of means"" who gets in stubborn Becky's good graces by engineering a vacation at the beach, then really delivers by getting pregnant. And it is kind, even-tempered Miss Cohen who helps exorcise Mama's vengeful ghost (i.e., Becky's guilt). That the story takes place in the Thirties and is set in Winnipeg is almost incidental: Becky's sights are set on a much narrower world, one bounded by family and friends. And within these close perimeters she proves to be an acute observer, both funny and fresh-mouthed, by turns naive and knowing; one whose childlike, screwy logic is well worth listening to whether she's discoursing on bosoms or the possibility of an afterlife.