光化学烟雾中最多的成分是（）。

A:PANs B:NO_x C:O₃ D:HCs E:醛类

（）, the brains of a computer, it contains the ALU, the clock, many registers, the bus interface, and circuitry that makes these pans work together.

A:I/O device B:CPU C:Memory D:Operating system

(71) , the brains of a computer, it contains the ALU, the clock, many registers, the bus interface, and circuitry that makes these pans work together.

A:I/O device B:CPU C:Memory D:Operating system

(71) , the brains of a computer, it contains the ALU, the clock, many registers, the bus interface, and circuitry that makes these pans work together.

A:I/O device B:CPU C:Memory D:Operating system

(71) , the brains of a computer, it contains the ALU, the clock, many registers, the bus interface, and circuitry that makes these pans work together.

A:I/O device B:CPU C:Memory D:Operating system