In the study, the researchers let volunteers read, play games and watch movies on a screen for different time while measuring how much light their eyes received.
Surely, please watch me in the hand mirror. I'll reach under the gum with a measuring instrument.
完全可以，请看手镜里我是怎样做的，我要用计量用具捅到牙龈底下。
3
An instrument other than a watch for measuring or indicating time, especially a mechanical or electronic device having a numbered dial and moving hands or a digital display.