DS6-K5B型计算机联锁系统，控显机双机与联锁机的两重系，通过（）构成交叉互联的冗余关系。
参考答案：光分路器
—Hi, Daming. It’s said the famous singer will come to Tai’an. Do you know ______?
—Next month.
A．when does he come
B．when he comes
C．when will he come
D．when he will come
爆破器材的临时保管地点，必须经当地有关部门批准，（）同时保管与爆破器利无关的物品。
A.严禁
B.可以
C.必须
