2013年6月20日，中国成为世界上第二个成功进行“太空授课”的国家。如图为太空授课中航天员用注射器向水球内注入空气，在水球内产生了 两个标准的球形气泡，气泡既没有被挤出水球也没有融合到一起，水球也没有爆裂。下列说法错误的是
A．实验是科学发现的重要手段，科学发现往往需要建立在实验事实的基础之上
B．水的分子组成和结构，在太空中没有发生改变
C．在太空实验中，如果往水球中分别注入氢气、氨气，同样也能观察到两个气泡
D．水球实验中，可用吸水纸捕获洒落的水滴
答案：C
题目分析：A、正确；B、没有发生化学变化，结构和化学性质不变，正确；C、氨气溶解于水，不能形成气泡，错误；D、吸水纸吸收水，可以捕获洒落的水滴，正确。
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| The purpose of a letter of application (求职信) is to help you to "sell" yourself. It should state 1 the job you want, and should tell what your abilities are and what you have 2 . It should be simple, human, personal and brief without 3 out any necessary facts. In writing a letter of application, keep in 4 that the things a possible employer is most 5 to want to know about are your qualifications(条件), your achievements and your aims. The opening paragraph is perhaps the most important part. 6 the first few sentences fail to 7 the reader's attention, the rest of the letter may not be 8 at all. Try to key your opening remarks to the needs or interests of the employer not 9 your own need or desires. For example, instead of beginning with "I saw your 10 in today's newspaper," you might say "I have made a careful 11 of your advertising during the past six months" or "I have made a survey in my neighborhood to find out how many housewives 12 your product and why they like it." Try to 13 generalities. Be clear about the kind of job for which you are now 14 . College graduates looking for their first positions often ask "What can I 15 in a letter? Employers want experience-which, naturally, no 16 has." The answer is that everything you have ever done is 17 . It is important to write a good strong closing for your letter. 18 a specific request for an interview or give the possible employer something definite to do or expect. An excellent 19 is to enclose(内附) a stamped, self-addressed envelope with your letter. That makes it 20 for a possible employer to get in touch with you. | ||||
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