城市热力管道工程施工要求中,穿墙套管长度应大于墙厚20~25mm,穿墙楼板的套管高度应高出地面( )mm。
A.45
B.50
C.55
D.60
参考答案:B
2x﹣1≤13中的最大值是m,不等式﹣3x﹣1≤﹣7中的最小值为n,则不等式nx+mn<mx的解集是x_________.
My sister likes watching sports on TV, _____ she doesn't play sports. [ ]
A. and
B. or
C. so
D. but