Where___his parents____(work)now,do you know?是填 are working 还是 dose work,为什么!

Where___his parents____(work)now,do you know?是填 are working 还是 dose work,为什么!
我是这样想的,这里有now,而且问地点也需用上be动词,所以可能用现在进行时;但是work不是动词词吗,动词不就是要用助动词do does did来修饰吗,所以我会疑惑不解,请帮我解答.