A:初级阶段
B:加速阶段
C:后期阶段
D:后期成熟阶段
某实验小组试图采用下图中的部分装置来探究“光照是光合作用的必要条件”(以观察装满水并倒置的试管中有无气泡产生作为实验指标),应选择( )
From his________look,I could see that he didn't believe what I said.