6到10题答案 只把二元一次方程列出来就行

6.will he
7.shouldn't he
8.do they
9.will you
10.need he

6 end off the friendship with this boy
7 being laughed at
8 to be happy 或 being happy
9 what she was interested in
10 why they disappear suddenly

six (siks)
seven('sevЗn）
eight(eit)
nine(nain)
ten(ten)

写起来不方便,先解释一下符号吧.
x^y：表示x的y次方
sqrt(x)：表示开根号x
sqrt(n,x)：表示开n次根号x
frac{x}{y}：表示以x为分子,y为分母的分数,即y分之x
lim就直接认定为n趋于无穷时候的情况吧.
(6)由于有公式:x^4-y^4=(x-y)(x^3+x^2*y+x*y^2+y^3)
所以,令x=sqrt(4,n^2+1),y=sqrt(n+1).
代入,则原式化为frac{-2n*sqrt(n)}{x^3+x^2*y+x*y^2+y^3}
（这一步上面的-2n既是根据x^4-y^4算出来的,下面写起来比较复杂,就直接代入了）
然后你既然之前的题都会做,应该到这里也会了吧,和（5）是一样的道理.可以上下同时除以n*sqrt(n).因为上下实际上关于n的次方数都是3/2,所以最后应该是剩一个常数的.最后得到-1/2.
方法肯定没错,得数不对的话跟我说一声,我得锻炼计算能力了……
(7)只要证明sqrt(n,1/n!)小于任意给定实数.就可以证明其极限为0.反证法.
即,假设存在k>0,使得对任意n,恒有sqrt(n,1/n!)>1/k,则1/n!>1/k^n.即对任意n,n!

6：DDCAC trying on a businesssuit in a blouse cotton tights a dress a miniskirt to an office catch more eyes suit atypical boy ACDBC CBAAD BCDAC
7：CDABC give me a loan What for support are spending hard up myself let him know get nowhere easy-going generalmanager my luck DCBAB BACDA BDCCC
8 BDDCA in prison the greater part of small office things three meals/3 meals get a break play gamesget fired all ears allow on the phonechange places In spite of BCDDA BACBC ADABD
9 CCADC driven through right awaysmells of run into going Look out hit it the opposite way BDACC ABDAC BBDAD
10 CCDDC two people/2 people What's up camping Care to snakes scared stiff in the mountains care for Poisonousones like can you or not how loud screamCBDAC CBADA DCBBA

先死记硬背,再做题.或者先画图,知道原理后记得就快了.

在室温下电阻率的大小只能作为判断材料是否金属或者绝缘体的大致参考数据.
实际上,半导体在低温下的电阻率也同绝缘体一样是很高的；半导体高掺杂后,将同金属一样电阻率是很低的.
例如,金刚石是绝缘体,但是它在高温下也是半导体（是制作高温晶体管的好材料）.

CABCD

who needed the communicating skills
which are being built
who has been affected
why this painting has been undervalued
which could not be readily gathered
这是哪个高中的高一.