钢板裂纹缺陷有什么特征？
参考答案：
在钢板表面有形状不同、深浅不等的裂口，一般呈鱼鳞状或水纹状。
—Did you watch the basketball match yesterday?
—Yes. You know, Jeremy Shu-How Lin, who is one of my heroes, ________ in the match.
A．is playing
B．has played
C．was playing
D．had played
混合床再生时,反洗分层的好坏主要与反洗分层时的阀门操作有关,与树脂的失效程度无关。
