如果|3x+3|+|x+3y-2|=0，那么点P（x，y）在第几象限？点Q（x+1，y-1）在坐标平面内的什么位置？

– Were you late for work yesterday morning?

– Yes. By the time I got to the bus stop, the early bus         .

A. has already left                B. is already left                 C. had already left