题干

下列化学用语中,数字“2”能用来表示分子个数的是(  )

A:2N

B:2Mg2+

C:2CO

D:O2

上一题 下一题 0.0难度 选择题 更新时间:2019-11-06 12:03:02

答案(点此获取答案解析)

C

同类题2

   Many textbooks are not written in the kind of English that we speak every day. In fact, sometimes the reading is so difficult that it almost seems like a foreign language. In a way, it is—the language of science. You should not expect to be able to read a difficult science passage the same way you read an interesting story; you should not expect to read it easily and all at once. Instead, you may have to read it several times through, catching on the meaning of difficult words, going back over difficult sentences, and finally putting the whole thing together. Do not be discourages if the whole passage don't make sense to you at first. You need to pick it apart patiently until you can understand it.
These are the steps to follow when you are reading something difficult:
   1. Start to read normally until you run into a sentence that doesn't make sense to you.
   2. When a sentence doesn't make sense, go back and read it again more slowly.
   3. Look for any word you don't know in the sentence. Try to understand their meanings using word parts and context clues(上下文线索). If necessary, look them up in the dictionary.
   4. Look at the next few sentences to see if they explain more about the sentence you are working on. Do not read very much farther ahead until you understand what is being said.
   5. Finally, read the sentence again. Try to put it into simpler words.
   6. Read through the passage once. Try to understand all the hard parts well. Then read the whole passage once more at a usual speed. This helps you to put all ides together.
   The stops sound a lot harder than they are. It is really just the normal way good readers understand anything that is difficult to read. After you have done the best you can this way, you should always feel free to ask for help from your teacher, if you have one.

同类题5

阅读下面两个文言语段,完成后面的题。
        【甲】环滁皆山也。其西南诸峰,林壑尤美。望之蔚然而深秀者,琅琊也。山行六七里,渐闻水声潺潺,而泻出于两峰之间者,酿泉也。峰回路转,有亭翼然临于泉上者,醉翁亭也。作亭者谁?山之僧智仙也。名之者谁?太守自谓也。太守与客来饮于此,饮少辄醉,而年又最高,故自号曰“醉翁”也。醉翁之意不在酒,在乎山水之间也。山水之乐,得之心而寓之酒也。 ……然而禽鸟知山林之乐,而不知人之乐;人知从太守游而乐,而不知太守之乐其乐也。醉能同其乐,醒能述以文者,太守也。太守谓谁?庐陵欧阳修也。(节选自《醉翁亭记》)
        【乙】欧阳修初谪滁山,自号“醉翁”,既老而衰且病,遂退于颍州,则又更号“六一居士”。客有问曰:“六一何谓也?”居士曰:“吾家藏书一万卷,集录三代以来金石遗文一千卷,有琴一张,有棋一局,而尝置酒一壶。”客曰:“是为五一尔,奈何?”居士曰:“以吾一翁,老于此五物之间,是岂不为六一乎!” 客笑曰:“子欲逃名乎?而屡易其号,此庄生所谓畏影而走乎日中者也。余将见子疾走、大喘、渴死,而君不得逃也。”居士曰:“吾固知名之不可逃,然亦知夫不必逃也。吾为此名,聊以志吾之乐尔。”  (节选自《诗人玉屑》)
       【注】①三代:指夏、商、周三代。(2)金石:指钟鼎文及碑文。