计算机室的一个墙面是长25米,宽4米的长方形,在这个墙面上贴墙纸,墙纸面积是( ),如果在它四周钉上木条,木条长约( )。
100平方米,58米
Three quarters of the forest ________ burnt to ashes, and the rest _______ cut down for construction. [ ]
A. was, have been
B. was, has been
C. have been, is
D. has been, are
回炼次品时,会对产品质量有什么影响?