强化接入型障碍管控，需健全哪几种故障的升级机制（）
A.重复故障
B.多次催修故障
C.超时故障
D.重大故障
参考答案：A, B, C, D
Unsatisfied ________ with the payment, he took the job just to get some work experience.
A．though was he
B．though he was
C．he was though
D．was he though
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