程控交换设备安装后必须有可靠的接地线，采用联合接地方式，其接地电阻不大于（）。
A.1Ω
B.4Ω
C.8Ω
D.10Ω
参考答案：A
When I stayed in the countryside，I enjoyed________leisurely walk in the fields，and felt________
warmth of the sun of my face.[ ]
A．/；the
B．a；a
C．/；a
D．a；the
Please send us all the information _________ you have about the candidate for the position.
A．that
B．which
C．as
D．what
