English

1.    Optical fibers are replacing conventional telephone_____________.

• wires and cables

• wires and codes

• calls and cables

• conversations and calls

What technologies did greatly improve the telephone system?

•   Communication technologies

•   Engineering technologies

• Digital technologies

• A.   Optical technologies

    What can serve as light wave conductors? 

•    ultra-thin silicon glasses

•   ultra-thin silicon cables

•    ultra-thin silicon discs

•    ultra-thin silicon fibers

   Optical transmission system most widely used now operates at ____ megabits per second.

• 147

• 247

• 747

• 547

    Optical transmission systems accommodate ____ circuits over a single pair of glass fibers.

• 7000

• 8000

• 6000

• 9000

   When were the first digital optical disks produced?

• in 1928

• in 1998

• in 1988

• in 1982

    The first digital optical disks were produced as ____ ____for music.

•   compact cassettes

•    compact disks

•    compact plastics

•   compact CDs

   The disks are made of _____coated with aluminum.

•   irons

• leads

•   plastics

•    metals

  A DVD-ROM can hold up to ___ GB.

• 17

• 27

• 72

• 77

A DVD-ROM can store a large amount of _______software.

• application

• computer

•   multimedia

• programming