Sacramento Country Day School soon could become the only high school in the grid. School officials are close to signing a lease for the Newton Booth School, 2600 V St., according to Stephen Repsher, Country Day headmaster. It also would mark the first time since 1976 that the Newton Booth School is being used as a school. Since closing because of earthquake concerns, it has been home to a medical insurance group and an environmental consulting group. "It could be in the next few weeks," Repsher said. "However, we still have to go to the city's planning commission and raise $1.7 million. We've moved a long way forward, but we're probably coming up in the next two to three weeks on some so