题目

2020年我市空气质量优良天数达 293天，监测大气污染物浓度的电路如图甲所示， R 为气敏电阻，其材料一般为 ______（填 “半导体”或“超导体”），气敏电阻阻值R 随污染物浓度变化曲线如图乙所示，污染物浓度增大时，监测仪表读数变大，该表应为图甲中 ______表，此过程中电路总功率 ______（填 “变大”“变小”或“不变”）。Only ____from university ____how difficult it was to make a good career. A．when did I graduate; I realizedB．when did I graduate; did I realize C．when I graduate; did I realizeD．when I graduated; did I realize