YC6LN-50系列气体发动机点火线圈1#过流的故障原因可能是()
A、点火脉宽较大
B、线路故障
C、点火线圈故障
D、ECU故障
参考答案:A, B, C, D
You can't complain of being left alone ________ you don't make any effort to meet people.[ ]
A. when
B. while
C. though
D. unless
在下述黏膜组织中,何处无黏膜下层()。
A.颊
B.唇
C.舌腹
D.口底
E.龈