装配螺塞时要求:()
A、用乐泰243螺纹锁固剂;
B、胶涂在螺塞底部所有螺纹处;
C、涂胶要求:四分之三圈;
D、将挤出的胶液清理干净。
参考答案:A, C, D
I haven’t seen Sara since she was a little girl, and she has changed beyond ____.
A.hearing
B.strength
C.recognition
D.measure
原子吸收分光光度法采用锐线光源是因为()
A.扣除背景吸收
B.增加测定灵敏度
C.测定被测组分的峰值吸收
D.去除谱线干扰