导线的加工有（ ）种方式？

After a while, John took the plunge and began to waltz ...

单项选择题After a while, John took the plunge and began to waltz with her, making her bend and sway to his direction, dominating every move she made.

气体检测无法检测出气体的____。A、是否存在B、种类C、浓度D、质量

单项选择题气体检测无法检测出气体的____。

系统工程强调反馈控制，问题导向并非其重点。

未知题型系统工程强调反馈控制，问题导向并非其重点。