通井时，通井规的外径应小于套管内径（）。
A、3～5mm
B、5～7mm
C、6～8mm
D、8～10mm
参考答案：C
Li Ming is _____ home from Beijing. [ ]
A. arrive
B. arrives
C. arriveing
D. arriving
The accident happened on such an evening with strong winds __________ by heavy rain.
A．appeared
B．happened
C．accompanied
D．mixed
