对流运动的水平范围一般为:().A.几千米 B.几十千米 C.几到几十千米 D.几百

题型:单项选择题

问题:

对流运动的水平范围一般为:().

A.几千米

B.几十千米

C.几到几十千米

D.几百千米

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DMY-15双翼旋转控制头包括2个阀,()个旋转头和4个低扭矩旋塞阀组成的双翼流动管汇。

题型:单项选择题

下列有关细胞信号转导的描述,哪项是错误的()。

A.心肌β受体兴奋引起cAMP增加,激活PKA,提高心肌收缩力

B.表皮生长因子可激活TPK,经Ras-ERK途径引起细胞增殖

C.内皮素受体兴奋可激活TPK,经PI3K途径促发肌肉收缩

D.M2胆碱能受体可激活Gi,减少cAMP生成,进而影响细胞的功能

E.NF可通过JAK-STAT途径影响靶基因的表达

题型:单项选择题

气候的基本要素是______和______________。

题型:单项选择题

阅读理解。

    Students who say they never or hardly ever used dictionaries often speak English well but usually write

poorly, because they make many mistakes.

    The students who use dictionaries most do not learn especially well either. The ones who look up every

new word do not read fast. Therefore they do not have time to read much. Those who use small two-language

dictionaries have the worst problems. Their dictionaries often give only one or two words as translations of

English. But one English word often has many translations in a foreign language and one foreign word has

many translations in English.

    The most successful students are those who use large college edition dictionaries with about 100,000

words but do not use them too often. When they are reading, these students first try to get the general idea

and understand new words from the context (上下文). Then they read again and use the dictionary to look

up only key words that they still do not understand. They use dictionaries more for writing. If they are not

sure how to spell a word, or divide it into syllables (音节), they always use a dictionary. Also, if they think

a noun might have an unusual plural form, they check these in a dictionary.

1. The writer thinks that _____. [ ]

A. choose a good dictionary, and you'll be successful in learning English

B. dictionaries are not necessary to the students who learn English

C. it is very important for students to use good dictionaries properly

D. using dictionaries very often can't help to improve writing

2. When does the writer advise students to use a good dictionary in the reading? [ ]

A. After the first reading

B. At the end of the reading

C. During the first reading

D. At the beginning of the reading

3. This passage mainly tells us _____. [ ]

A. that students shouldn't use small two-language dictionaries

B. that the small two-language dictionaries are very useful

C. why students should use large college edition dictionaries

D. what dictionary students should choose and how to use it

4. Which is not mentioned in this passage? [ ]

A. How to make good use of a dictionary.

B. How to improve spoken English.

C. When to use a dictionary.

D. How to practise reading fast.

题型:单项选择题

“三、二、一”产业中,属于第三产业的是( )P1

A.渔业

B.交通运输

C.水的生产和供应业

D.建筑业

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