乙型肝炎病毒常发生（）。
A.隐性感染
B.急性（病原消灭型）感染
C.慢性感染
D.潜伏感染
E.慢发病毒感染
参考答案：A
解析：3.乙型肝炎病毒常发生隐性感染，即病原体侵入人体后，仅引起机体产生特异性的免疫应答，不引起或只引起轻微的组织损伤，因而在临床上不显出任何症状、体征，甚至生化改变，只能通过免疫学检查才能发现。水痘-带状疱疹病毒常发生潜伏感染，即初次感染表现为水痘，以后病毒可长期潜伏在脊髓后根神经节，免疫功能减弱可诱发水痘带状疱疹病毒再度活动，生长繁殖，沿周围神经波及皮肤，发生带状疱疹。人免疫缺陷病毒常发生慢发病毒感染，即经显性或隐性感染后，病毒有很长的潜伏期，此时机体无症状，也分离不出病毒，以后出现慢性、进行性疾病，常导致死亡。
Now students’ English handwriting（书法）gets worse and worse. That makes their teachers feel worried. Is your English handwriting beautiful? If not, here are four steps that really work! Using paper with lines(线条) can keep you writing straight instead of up or down when you write English words or sentences. Those lines on the paper can help you to write words in the right size. Be sure to fill the lined space completely. If your writing is hard to read, try slowing down a little. For some kids, going slower makes the handwriting clear. If you write too fast, it’s hard for you to stop where you should, and even worse, you may make more mistakes. When you hold your pencil the correct way, writing is much easier. Try to be relaxed and don’t hold the pencil so hard while writing, and then it makes your handwriting nice and clean. If you do so, people will guess you are a student with a good habit. Drawing can improve your handwriting. You need to use the skills to control(控制) your pencil better when you are drawing pictures. Even though you have no chance to draw at school, you can practice by yourself at home.
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