双向锁定封隔器由芯轴和()分别带有左、右旋金属齿形螺纹的锁块组成。
A、一对
B、二对
C、三对
D、四对
参考答案:B
How can the students carry on with the listening test with all that loud noise _________?
A.going on
B.goes on
C.went on
D.to go on
请结合《信客》上下文解释词语。
①闯码头:_______________________
②吊唁:_______________________
③穷愁潦倒:_______________________