音节“qi”可以由“（）”两个特定码。
A、期和七
B、其和七
C、七和期
D、其和期
参考答案：D
She felt she had looked at the problem from every___ . [ ]
A. field
B. direction
C. aspect
D. place
滴定操作中，滴加半滴如何操作？
