2022智慧上进2020文综七答案

2022智慧上进2020文综七答案，目前我们已经整理了2022智慧上进2020文综七答案的各科答案和试卷，更多智慧上进请关注本网站。

书面表达:A Meaningful Volunteer ActivitA volunteer activity was organized by our school in the railway station last weekend. The activity was de-signed to help the passengers who needed help. Meanwhile, our teachers required us to seize the chance tospread kindness. Twenty students including me actively took part in the activity and we devoted ourselves tohelping the passengers. We helped to carry luggage and led the way for them. In addition, we bought some wa-ter and food to the elderly passengers.This volunteer activity was meaningful and valuable. Through the activity, we developed a good relationship. More importantly, I learned that even a small kindness can make a big difference to others and warm uptheir hearts

12.B【解析】一条含有11个肽键的多肽链,则含有12个氨基酸。mRNA中每3个相邻的碱基决定一个氨基酸;一个氨基酸需要一个tRNA来转运,因此mRNA中至少含有36个碱基,至少需要12个tRNA,DNA中至少含有72个碱基。故选B。