问题 填空题

某同学在实验室对粗盐进行溶解、过滤、蒸发的实验操作.

(1)经过两次过滤后,滤液依然浑浊.经检查,发现滤纸没有破损,所用的仪器也很干净.原因可能是______.

(2)在实验 的三个步骤中都要用到同一种常见的玻璃仪器,此仪器名称是______.

答案

(1)用洗净的仪器进行过滤操作时,滤纸未破损,经两次过滤后,滤液仍浑浊.因为漏斗中的液面高于滤纸的上边缘.故答案为:漏斗中液面高于滤纸边缘

(2)在三个步骤中都要用到同一种玻璃仪器是玻璃棒,故答案为:玻璃棒

单项选择题
阅读理解

下面文章中有5个段落需要添加首句。请从以下选项(A、B、C、D、E和F)选出适合各段落的首句,并在答题纸上将相应选项的标号涂黑。选项中有一项是多余选项。

A. Time can run out.

B. Tomorrow won’t be better.

C. Ideas need time to develop.

D. Your professor will be impatient.

E. You blow off your chances for help.

F. You are probably overestimating (高估)the pain.

Never Put off Tomorrow What You Can Do Today

Want to put off studying for the physics test? Or writing that thirty-five-page research paper on future uses of biotechnology? Sure you do? And who wouldn’t? But it’s still a silly idea to put off doing something until a future time. Here is why ....

小题1:__________. The task will be still the same. It won’t be any more fun and you still won’t want to do it. As the deadline gets closer and closer, the task seems to become larger and larger if you haven’t started the work. And the stress increases. Now not only do you have to write that paper, you have to do it under great pressure.

小题2:_________ . Before you start, it seems that the task is unlikely to be accomplished. But you know what? You’re probably miscalculating. Get started -------- maybe on a small piece ------ And you will discover that you have more resources and know more about the subject than you thought. Result? You won’t experience nearly as much suffering as you expected to. Things are guaranteed ------ 100 percent ------- to get better.

小题3:_____________ . If you leave your work before the night before it’s due, you give up the possibility of getting input from your professor. Professors regularly give advice ----- or at least a few useful tips ---- during office hours. Unfortunately though, they don’t usually hold office hours at midnight, so you will be out of luck when you discover the night before the midterm that you have no idea how to do the questions that will count for two-thirds of your grade.

小题4:________ . Ever wonder why the professor assigns the papers two weeks before it’s due? It’s because he or she expects you to be thinking about the issue, or doing the research, for two weeks. No, not every waking moment, but at least some of the time. After all, the professor could just as easily have given the assignment one week before it was due if he or she expected less thinking. When you throw together a paper or a report at the last minute, your ideas are half-baked. And your professor will know it.

小题5:________ . If you put things off at the last minute, you might find that you haven’t budgeted enough minutes to finish the necessary tasks. It’s the easiest thing in the world to miscalculate how long it will take to do all the work especially when new issues arise ------ like illness, family problems, computer breakdowns, trouble at work, and all the other things ------- as you are thinking through your paper argument or preparing yourself for the coming test. If you keep delaying, you don’t allow yourself time for those various life events that have an adverse(不利的) effect on your ability to complete your assignment.