2022吉林版英语周报答案

12.D【解析】因为f(x)是定义域为R的奇函数,所以f(0)=0.因为f(x+4)-f(x)=f(2),令x=-2,得f(-2+4)f(-2)+f(2),即f(2)=f(-2)+f(2),所以f(-2)=0.又因为f(x)为奇函数,所以f(2)=-f(-2)=0,所以f(x+4)=f(x)+f(2)=f(x),所以f(x)是以4为周期的周期函数根据周期性及奇函数的性质画出函数y=f(x)在[-4,4]上的图象,如图由图可知,函数y=f(x)在[一4,4]上有零点-4,-3.5,-3,-2,-1,-0.5,0,0.5,1,2,3,3.5,4,共13个零点

One possible versionSeveral minutes later, the ice broke suddenly and Harry's feet sank into the water. It was noep, but his legs got wet to the knees. Harry was so upset that the accident would delay hisschedule. He had to find some firewood to build a fire to dry his clothes. He pulled off his glovestook out his matches, and lighted the fire. Seeing the burning fire, he had thought he was safe. Butsuddenly, without warming, a heavy mass of snow dropped down. The flame of hope was put outUnluckily, his dog ran away and the fear of death came over Harry. He had no choice but torun to save himself. However, he did not feel his feet when they hit the ground. Having falleneveral times, he decided to rest a while. As he lay in the snow, he noticed he was not shaking. Hecould not feel his nose or fingers or feet. A feeling of horror came into his mind. It was when herealized he was going to die that he heard a bark and the noise his friends made

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