20xx外研版(一起)六上unit2standinline!

2，且 an+1= ，求 {an}的通项公式． 212 na an+1=can+f(n)型 (1)若 f(n)=kn+b(其中 k,b为常数 ,且 k≠0), 例：在数列 {an}中 ,a1=1,an+1=3an+2n,求 an. 待定系数法：设 an+1+A（ n+1） +B=c(an +An+B),求出 A、B，转化为等比数列求通项 . 例 （ 1） 设 a1=1，且

Laura is from England. 2. Can Daming speak English? Yes, he can. 3. Daming has got two friends from England. Who are they ? They are Sam and Amy . Daming be Laura’s Chinese pen friend?

an, other than, rather than, 2）词性辨析： [例 1]____ had I done it when I knew I had made a mistake. A. Hardly B. Directly C. Mostly D. Nearly [例 2]____ I meet Mary in the street, she will greet me with a

e than two thousand years old. • It’s twenty metres tall. • The clock is fifty metres high. • It’s two hundred years old. • I’m going to send an to Mum. • Yesterday I had a big surprise. • There were

后接动词原形 Read,write and ，写一写，说一说 • 1)You _________________(tidy up your books). • 2)You ___________________(jump on the bed). • 3)You ___________________(draw on the wall). • 4)You

ingling’s favourite skirt is dirty. Sam’s shoes are wet and dirty. 判断正误 Today is a sunny day. Amy’s black dress is wet. Lingling’s favourite skirt is dirty. Sam’s shoes are wet and dirty. 判断正误 Today