把“紅綠燈”看成一個整體時,用traffic light,單數。表達它有三盞燈時,用three lights,複數。
The traffic light has three lights, red, yellow and green.
紅綠燈有三盞燈,紅燈、黃燈,和綠燈。
Red is on top, yellow is in the middle, and green is on the bottom.
紅燈在上面,黃燈在中間,綠燈在下面。
注:on top和on the top都可以,但是on bottom不行。