转盘定位后，（）应与井口中心重合，允许误差不得超过规定标准。
参考答案：转盘中心
_________ you may have, you should gather your courage to face the challenge.
A．Whatever serious a problem
B．However serious a problem
C．However a serious problem
D．No matter how a serious problem
水体污染监测分析方法有哪些，怎样选择？
