工作压力为1.2MPа，DN150法兰密封面与管道中心线的垂直度的允许偏差为（）mm。
A.±1
B.±2
C.±3
参考答案：B
生物只能适应环境不能改变环境．______．
—Who likes playing ______ volleyball?
—My sister ______. [ ]
A. the; likes
B. /, likes
C. /, does
D. the, does
