来电显示 lai dian xian3shi4 (caller ID)
你能不能充分利用你的手机？ (Do you make the best use of your mobile phone?)
For example, under some plans you have to select caller ID so that you can see who is calling you when the phone rings. (You actually pay an extra 2 RMB a month for this service.) Turning it on requires listening to the automatic phone company service and making the appropriate selections. It's not easy; I asked at a phone shop for someone to help me.
请你帮助我打开来电显示，好不好？ (Can you help me turn on caller ID please?)
Does anyone have some other helpful expressions to do with using your mobile phone in China?