Bacteria came into a ventilation system when______.A．cool air was sucked into itB．warm air

_______ came into service in the early 1980s.A、The cometB、The Boeing 747C、The Boeing 757

I found a letter lying on the floor when I came into the classroom.（)

It can be inferred that railroad refrigerator cars came into use ______.A．before 1860B．bef

Microcomputers （) with the invention of microchips.A、appearedB、turned upC、came into bein

Unlike Britain, Australia has a written Constitution, which came into effect inA．1911.B．19

They were arguing but _____ off when someone suddenly came into the room.A.tookB.tur