闸机通道传感器属于哪种类型（）
A.光电传感器
B.接近传感器
C.压力传感器
D.流量传感器
参考答案：A
He wanted to know _______
A．why he bought the present for
B．which room he lived in the hotel
C．who he had travelled with
D．who has been chosen to be the chairperson
为保证船舶具有足够的储备浮力，客货船常采用（）不沉制。
A.一舱
B.二舱
C.三舱
D.四舱
