科学家常用哺乳动物红细胞作材料研究细胞膜的组成,是因为() A.哺乳动物红细胞的细胞

题型:单项选择题

问题:

科学家常用哺乳动物红细胞作材料研究细胞膜的组成,是因为()

A.哺乳动物红细胞的细胞膜在光学显微镜下容易观察到

B.哺乳动物红细胞容易得到

C.哺乳动物红细胞在水中容易涨破

D.哺乳动物成熟的红细胞内没有核膜、线粒体膜等膜结构

考点:高中生物细胞的结构与功能细胞的结构与功能题库
题型:单项选择题

对话填空。

     阅读下面对话,掌握其大意,并根据所给首字母的提示,在标有题号的右边横线上写出一个

英语单词的完整、正确形式,使对话通顺。

Dilys ---- D;         Aubrey --- A

D: Hello, Aubrey.

A: Hi, Dilys.

D: Why weren't you at the French class last night? Have you(1)g ____ up?

A: Well, no … I came back late yesterday and found Jackson(2)s____ there. He'd been

   writing(3)r ____ all day long and he was too tired to go out again, so we gave the lesson a miss.

D: You've(4)m_____ quite a lot of the lessons(5)l ____, haven't you? Are you losing interest?

A: Yes, I'm afraid so. Neither Jackson nor I have a gift for languages. People just(6)l ____ at us

   when we(7)a____ to speak French. How did you and Alice pick it up so quickly and easily? You've

   (8)h ____ been in Paris half a year.

D: It was neither quick nor easy. We'd both studied the language before we came, and we only needed

   to(9)r ____ it.

A: (10)A _____, all our friends here speak English very well, so we don't really need to learn French.

题型:单项选择题

If possible I'll _____ rockets _____ the moon and Mars.  [ ]

A. be; to

B. fly; on

C. be; on

D. fly; to

题型:单项选择题

_____ the police arrived, the thief ran away.              [ ]

A. When

B. Before

C. After

D. While

题型:单项选择题

糖尿病酮症酸中毒的早期表现为()

A.呼吸有烂苹果味

B.多尿,烦渴多饮

C.皮肤弹性差

D.嗜睡

E.血压下降

题型:单项选择题

()是导致烧心症状的关键因素

A.胃酸

B.咳嗽

C.哮喘

D.腹痛

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