题目

I have been working at Papworth Hospital in Cambridge for the past 20 years. My day starts at 5:30, when I have two cups of black coffee while listening to the radio. Recently, I've been using the morning to work on a book I'm currently writing. I'm in the hospital just before 8:00. If it's a nice day, I'll cycle the fifteen miles to my office, but my favorite way of getting to work is on my motorbike. My week is divided into operating and non-operating days. Monday and Tuesday are my operating days and I like to come in early and stay late to check the progress of my patients. During the rest在演示双缝干涉的实验时，常用激光做光源，这主要是应用激光的什么特性？（   ）A．亮度高B．平行性好C．单色性好D．波动性好