You might make a disgusted face when you notice that the person waiting in their car at the red light next to you is picking their nose,but admit it,you do it too.And while it might be the natural option when there isn't a box of tissues around,it can be bad for you.The main reasons people feel the need to pick their nose is to clear it of dried liquid,stop an itch（痒）,or just because it feels good.Boogers（鼻屎）form when dried liquid and cilia,the tiny hairs that line the nostrils（鼻孔）,trap the dust,dirt,and other things.When boogers build up in your nose,it can be uncomfortable,and sometimes just blowing into a tissue doesn't do the trick.

    Otolaryngologist Erich P.Voigt, MD ,told Business Insider that picking your nose can cause injuries and bleeding within your nostrils.That's not terribly damaging,but when the bacteria from your hands get into your body,it can cause a cold and flu.So doctors strongly suggest not picking the nose.

    If dry winter air is causing the dirty liquid to harden in your nostrils,making you want to pick,consider damping the air at home,or taking a steam shower to soften things up in there.

    Children, who are most famous for having a finger up their nose,sometimes don't realize how much injury they're causing,and sometimes it.can lead to nose bleeds.

    So, next time you go to pick your nose,think about how many bacteria are on your hands and in your boogers, and maybe reach for a tissue instead.Even if you 're alone,and not waiting for the light to turn green,please,use a tissue.

（Ⅰ）求数列{a_n}的通项公式；

（Ⅱ）设数列b_n= $\frac{1}{{\left(2{\log }_2{a}_{n+1}+3\right)}^2-1}$ ，且数列b_n的前n项的和T_n，试比较T_n与 $\frac{1}{4}$ 的大小．

 废金属主要指____、____、____的金属物品等。