A：注射该疫苗，人体先利用第一道防线阻止，然后再引起体内非特异性免疫（即第二道防线）和特异性免疫
B：该疫苗引起免疫反应前必须经过转录和翻译过程
C：注射该疫苗后，B淋巴细胞分化为浆细胞的过程中，内质网膜会减少，高尔基体膜保持不变，细胞膜会增加
D：注射该疫苗后，如果感染该病原体，机体内记忆细胞的细胞周期将变长
治理黄河的根本措施是（ ）
敬爱的加利先生；在此，我代表我的家庭，代表所有的中国孩子，通过您向整个国际社会呼吁：“救救孩子们，要和平不要战争！”为了母亲不再失去儿子，为了妻子不再失去丈夫，为了孩子不再失去父亲，全世界应该一致行动起来，维护和平，制止战争！让那已经能够听到脚步声的21世纪，为战争敲响丧钟，让明天的世界真正成为充满阳光、鲜花和爱的人类家园！
A
Problems
Causes
Advice
Feel stressed
Too much homework. Don't have enough time for their hobbies.
Make a plan for study and hobbies. Find time to relax.
Get short sighted (近视)
Too much homework. Bad study habits.
Do homework or read in a correct way.
Fight with each other
Don't know how to get on well with classmates.
Make more friends and understand each other.
Don't like to study
Play computer games too much.
Play computer games just for a short time.
Get fat
Have more pocket money to buy snacks. Don't like to do exercise.
Use your pocket money to do something meaningful. Do exercise every day.
一组数据5，4，2，5，6的中位数是（ ）
