题目

GRANTS PASS, Oregon: An American couple letting their SUV’s navigation system guide them through the high desert of the state of Oregon got stuck in snow for three days when the GPS unit sent them down a remote forest road. On Sunday, their GPS-enabled cell phone got a weak signal and relay coordinates（坐标） to a dispatcher（调度员）, Klamath County Sheriff（警长） Tim Evinger said. “GPS almost did them in and GPS saved them, Evinger said. “It will give you options to pick the shortest route. You certainly get the shortest route. But it may not be a safe route.” Evinger碳酸氢铵是符合国家食品安全、允许使用的食品添加剂，用在需膨松较大的西饼之中．化学式是NH4HCO3，根据以上材料，按要求完成下列带点部分的化学用语：在________，其水溶液中的阳离子为________ 碳酸氢铵在受热时会分解为________、水和二氧化碳．由于含有________，它可作为化学肥料．