Any of several harmless American snakes.

美洲之无毒蛇。

The poisonous viper of Europe.

欧洲的一种毒蛇；蝮蛇。

In Central Procession Unit (CPU), the circuitry that adds two numbers. There are full adder and half adder according to whether the carry exists or not in the result.

在中央处理器(CPU)当中，用来将两个数值相加的线路。依照加法是否包含进位功能的不同，有全加器(full adder)和半加器(half adder)之分。