人的眼睛像一架神奇的照相机，晶状体相当于照相机的____镜，外界物体在视网膜上所成的像是____的实像．（选填“正立”或“倒立”）．常见的视力缺陷有____和____．来自远方物体的光，经眼球折光系统折射后成像情况如图所示．根据该光路图，这个人可配戴____透镜的眼镜加以矫正，它的作用是使像相对于晶状体向____（选填“前”或“后”）移．

    Are you a-teenager____ (absorb) in music? If so, I will give you a warning – the music you love could end up making you deaf. More ____(specific), the way you listen to the music you love could make you deaf.

    The problem is .headphones. In the past, we played music out into the air. Then earmuff-style（耳罩式）headphones ____ (invent) and we were able to play music much closer to our eras. Now we have earbuds（耳塞）, which many doctors think are ____ (bad) than older headphones because they play music directly into the eras. Also, earbuds are not as good as blocking outside noise, so people____ use them nay turn the volume ____ to dangerous levels.

    What's the dangerous level? Well, it ____(depend) on how long you are going to listen to the noise. Very, very loud sounds can be dangerous to your hearing. But the scary ____(true) is that even seemingly “normal” noise can be dangerous ____you listen to it all the time.

    Think for a minute about how long you spend ____ (listen) to loud noise with headphones every day. Then do some research. There are resources online telling you what volumes are safe, and for how long.

从《悯农》中找出下列词的反义词。

春—____   种—____   有—____

忙—____   饱—____   活—____

①钠的化合物②能与硝酸反应的物质 ③可溶于水的物质 ④水溶液导电 ⑤钠盐 ⑥钠的含氧化合物．