A roof pipe chase housing system for allowing pipes to pass through a roof without leaking. the pressing member is rotatable related to the worktable between a first position and a second position. A contact hole is formed on the negative line and the drain electrode, and a bridge electrode connects the negative line and the drain electrode through the contact hole. In another embodiment, high voltage transistors are used to selectively isolate the bit lines from and couple the bit lines to a peripheral circuit in pairs so that each high voltage transistor is shared by two bit lines. A connector secures the pedal arm to the support member for normal operation, and permits separation of the pedal arm from the support member in response to a reward force resulting from a collision impact.