They are all abbreviations, taking the first letter of each letter.
Pencil HB means that the hardness of lead is HB, which is divided into 2H H HB B 2B, and the hardness of lead becomes smaller in sequence.
CD stands for small laser disk, which is used for all General term for CD media formats. CD formats currently on the market include audio CD, CD-ROM, CD-ROM XA, photo CD, CD-I and video CD, etc.?
British Broadcasting Corporation (British Broadcasting Corporation, BBC), is a media with high visibility in the world
Common ones include:
APC Asian Petroleum Company
BC BC
PLA Chinese People's Liberation Army
RMB Renminbi
CCP Communist Party of China
BA British Airways
SARS
NAB National Association of Broadcasters
TV TV
PRC People's Republic of China
TM trademark
UK United Kingdom
USA United States
BBC British Broadcasting Corporation
ABC American Broadcasting Corporation
CBC Canadian Broadcasting Corporation Company
CAAC China Civil Aviation
DDD International Direct Dial Telephone
IDD International Direct Dial Telephone
IT Information Technology
WTO World Trade Organization
WHO World Health Organization
CAD Computer Aided Device
CAM Computer Aided Manufacturing
IBM International Business Machines Corporation
PC personal computer
ALU operator
I/O input-output
ISA industry standard structure
RAM random access memory
ROM read-only memory
VGA video image array
IDE is an interface specification for the development of small and medium-sized hard disks (upper limit is 540MB)
CSCI National Science Document Service System
COMI COM1 COM2 serial port
MPC multimedia computer
JPEG still image compression standard
CD-ROM optical drive
BIOS basic input/output system
COMS complementary metal oxide semiconductor
ISO International Organization for Standardization (ISO, International Organization for Stan-dardization abbreviation)
vip VIP.
usa (United States Of America) United States of America; United States
cctv (China Central Television) China Central Television
bbc (British Broadcasting Corporation) British Broadcasting Corporation
prc (People's Republic of China) People's Republic of China=.=
un (United Nation )United Nations
pm afternoon.
W.C Toilet
CN China
P Parking Lot
BTW-- --BY THE WAY-By the way