A:以下是从标准里摘录的几段文字解释: 3 Designations 3.1 Glass bulbs shall be described by a designation consisting of the following sequence of letter and number symbols, without spaces in between, as follows: a) A first letter symbol consisting of up to three letters which describes the bulb shape. The letter or letters of this symbol may in some cases be a basic shape letter symbol only and in other cases i
A:以下是从标准里摘录的几段文字解释: 3 Designations 3.1 Glass bulbs shall be described by a designation consisting of the following sequence of letter and number symbols, without spaces in between, as follows: a) A first letter symbol consisting of up to three letters which describes the bulb shape. The letter or letters of this symbol may in some cases be a basic shape letter symbol only and in other cases i