黄酮类化合物能产生颜色的主要原因是() ["含有多个酚羟基","含有多个醇羟基","有助色团","有显色团","有交叉共轭体系"]
锅炉在正常运行时,应根据实际情况随时调节水位()除灰、排污等。 ["A、汽压","B、风量","C、汽温","D、火焰"]
地图印刷采用的方法是()。 ["凸版印刷","平版印刷","凹版印刷","喷墨印刷"]
玄参的加工方法是() ["刮去粗皮,加工成卵圆形或圆柱形,或切成厚片干燥","堆放3~6天"发汗",反复数次至内部变黑色,再晒干或烘干","曝晒至半干,反复搓揉,边晒边搓,至全干,撞至表面光滑","撞去表皮,加煅过的贝壳粉,吸去浆汁,干燥","置沸水中烫或煮至透心,刮去外皮晒干撞至表面光滑"]
抗链球菌溶血素"O"升高,常见于A族溶血性链球菌感染引起的疾病,但不包括() ["风湿热","心肌梗死","扁桃体炎","感染性心内膜炎","链球菌感染后肾小球肾炎"]
室内配电箱可落地安装,也可()或()于墙壁上。