外护层标准中规定裸铠装用钢带应用（）。
A.普通钢带
B.涂漆钢带
C.镀锌钢带
D.预涂钢带
参考答案：C
Only an hour ago ________ out why he was absent.
A．did the teacher found
B．the teacher found
C．did the teacher find
D．had the teacher found
在PS版显影机中，如果显影液的喷放量小，易造成显影液的加速氧化，使显影液失去作用。
