traffic lights 是is 还是are

the traffic lights还是the traffic light how many traffic lights are there? There are always （ ）lights in traffic they are traffic lights上一句是什么 the traffic lights are green.we can[ ] the traffic lights are yellow.we can [ ] My favorite invention is lights.用is还是are the traffic lights的意思是? there are （） traffic lights in every country there are three traffic lights in every country. every the same county traffic are lights in the 连句：are,there,in,country,three,lights,every,traffic