—It's so exciting that I _______ it twice.
A:am reading
B:have read
C:was reading
D:had read
(1)先在试管中加入2mL硫酸铜溶液,然后滴入几滴氢氧化钠溶液,此实验操作需要的仪器除试管外,还需要____ .
(2)如图所示的实验中,将注射器的活塞向右拉时,若装置不漏气可观察到的现象是____