问题
单项选择题
钢材表面处理的质量等级要求，()金属表面处理质量等级分为两级。
A.喷射或抛射除锈
B.手工或动力工具除锈
C.火焰除锈
D.化学除锈
答案
参考答案：B
搜题请搜索小程序“爱下问搜题”
钢材表面处理的质量等级要求，()金属表面处理质量等级分为两级。
A.喷射或抛射除锈
B.手工或动力工具除锈
C.火焰除锈
D.化学除锈
参考答案：B
What is the point the speaker is trying to make about technology development
A．A mature technology requires less innovation.
B．Technical evolution is close to maturation in certain fields.
C．New types of energy are expected to mature in the near future.
D．Nanomaterials or photonics and carbon nanotubes are environmentally friendly.