- 搜标题
- 搜题干
- 搜选项
单项选择题
Fill in the blank with the most appropriate choice.Two questionnaires __________ for the survey based on two earlier survey instruments by Taylor & Hussein (1985) and Guo (1989).
Fill in the blank with the most appropriate choice.Two questionnaires __________ for the survey based on two earlier survey instruments by Taylor & Hussein (1985) and Guo (1989).
A、were developed
B、were developing
C、developed
D、developing
是调制信号
的线性搬移。 
