The light is still on. Why not ______?

A． turn it on

B． turn it off

C． turn on it

D． turn off it

[单选题]—The light in his room is still on. Do you know??____________?—In order to prepare for the coming exam.A． if he works hard B. why he stays up so lateC． why is he so busy D. when he will stop working

[试题]6.Why can’t ultraviolet light scorch our skin on E［A］BecausetheEarth’satmospherecanmakeultravioletlightlessharmful.［B］Becauseultravioletcan’treachtheEarthatall.［C］BecausetheEarthisfarawayfromthoseplanetsradiatingultravioletlight.［D］Becauseotherspacepl

[单选题]The passage focuses on .A． why Pepperberg decided to carry out the experimentB． how Pepperberg proved her theory abottt animals' thoughtsC． the new way of communication Pepperberg proposedD． the problems that Pepperberg faced in the experiment

[单选题]______no need ______ the radio as I’ve used to studying with it on.A.It’s;

[名词解释] Still病

[单选题]E．lectromagnetic EnergyWhite light seems to be a combination of all colors. The energy that comes from a source of light is not limited to the kind of energy you can see. Heat is given off by a flame or an electric light. On a cloudy day it is possib

[名词解释] 环境光（Ambient light）

[试题]“Thislightistoo______formetoreadby.Don’twehaveabrighterbulbsomewhere”;saidtheelderlyman.A．)mildB)dimC)minuteD)slight

[名词解释] 光反应(light reactions)

[单选题]I tried to get outof the business _____I found impossible to carry on.A.why