13．录像带＿＿＿＿＿＿＿＿＿＿＿＿＿ 14．把．．．带到．．．＿＿＿＿＿＿＿＿＿——青夏教育精英家教网—

摘要：13．录像带＿＿＿＿＿＿＿＿＿＿＿＿＿ 14．把．．．带到．．．＿＿＿＿＿＿＿＿＿

网址：http://m.1010jiajiao.com/timu3_id_2674949[举报]

David,an ＿＿boy can write in Chinese.

A. 8＿years＿old B. 8＿years C. 8＿year＿old D. 8＿years old

炭疽热是由炭疽芽孢杆菌引起的，该细菌可引起动物组织水肿、粘膜出血，幷可造成动物死亡。法国科学家巴斯德在研究牲畜炭疽病时进行了如下实验：给实验绵羊注射毒性已削弱的炭疽芽孢杆菌制剂，这些绵羊感染后没有发病。四天后，给实验绵羊注射毒性极强的炭疽芽孢杆菌制剂，经过一段时间后，实验绵羊全部正常生活。根据以上资料，回答以下问题。
（1）实验绵羊在第二次注射炭疽芽孢杆菌制剂后没有发病，其原理是体内产生＿＿＿＿，该物质的化学本质是＿＿＿＿，它是由＿＿＿＿细胞产生分泌的。与之合成和分泌相关的细胞器有＿＿＿＿＿＿＿＿＿＿＿＿，这种免疫属于＿＿＿＿免疫。
（2）如果不能确定第二次注射的炭疽芽孢杆菌对实验绵羊的毒性是否极强，需要改进实验设计，请在上述实验的基础上补充相应的实验设计原则、步骤。
①实验设计原则：＿＿＿＿＿＿＿＿＿＿＿＿
②操作步骤：＿＿＿＿＿＿＿＿＿＿＿＿查看习题详情和答案>>

Cinderella has to do all the housework. She makes the beds. She watches the clothes. She cleans the room. She ＿＿ the meals. She goes shopping_____the family.

One day, the family goes to a ＿＿ at the prince’s palace （皇宫）. Cinderella is ＿＿. She says, “I want to go and dance, too! ”

Then, a fairy(仙女) comes and says, “I can help you. ” She gives Cinderella a party dress and a pair of glass ＿＿. Then she says, “Come home early. You must get home before 12:00___”

Cinderella goes to the party and ＿＿ with the prince. She forgets about the＿＿. Then she sees a clock. It is almost midnight. Cinderella ＿＿ home and she gets home right at 12:00, ______she loses one of her glass shoes on the way.

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