硼氢化钾—硝酸银分光光度法测定水中痕量砷时，如果样品巾有机质太多，用高氯酸消解时易发生爆炸，所以需放置待无气泡时再升温消解。
参考答案：对
—Mr Wang was caught in a snowstorm yesterday.
—I have known that，and_______his new car was completely destroyed.
A．hopefully
B．fortunately
C．thankfully
D．unfortunately
诊断急性阑尾炎最重要的体征是（ ）
A．右下腹有肌紧张
B．右下腹有反跳痛
C．右下腹有明显固定压痛点
D．闭孔内肌试验阳性
E．结肠充气试验阳性
