题目

My grandfather once said, “To know yourself, you have to know those who came before you.” He didn’t just say those words; he_______by them. In 1996, my grandfather moved to the United States to care for me and my sister. The decision to leave behind 65 years of family relationships was_______. And he was forced to fit his entire life into two suitcases---one with clothes and books; the other with the_______of long-lost relatives. As we looked through the photos, I saw his face_______with a strong desire to return to those happy times.Some of the photographs were from the nineteenth centuN2经一系列过程可以得到HNO3和NH4HCO3，如下图所示。 （1）过程 ______ 属于“氮的固定”。（2）过程Ⅱ，NH3和O2在催化剂作用下反应，其化学方程式是________。（3）过程Ⅳ，为使NO2尽可能多地被水吸收，需不断的向反应器中通入________。（4）NH4HCO3常用作铵态氮肥，但不宜在碱性较强的土壤中施用，原因是______。