题目内容：

Too many people think that intelligence is a gift of nature and that there is little anyone can do to improve theirs. IQ tests have managed to confuse many of us, leading us to believe that intelligence is largely fixed.

It is not. Just like swimming, cooking, dancing, and many other things, being smart is a skill that requires training. I discovered some of the most important tools to be smart when I watched my professors for years to learn how to do useful research. Now I will share them with you.

Practice self-critical thinking

Critical thinking is the act of questioning the arguments that are put before us. It is a valuable skill — without it, we are too willing to believe what other people say and easily get influenced. The problem is that we usually only apply (应用) critical thinking to other people's ideas. When we apply critical thinking to our own ideas, its power reaches a whole new level. I call this self-critical thinking. If you practice self-critical thinking, you will find imperfection in your arguments before anyone else. And you can come up with a better idea. By practicing self-critical thinking, your mind will surprise you.

Be persistent

Smart and successful people don't give up. They believe that they can do it, so they spent months, even years trying until finally something works out. You might know that Thomas Edison failed thousands of times before he succeeded. Actually, almost all scientists experience failure regularly. So if you want to be smart, be persistent.

Learn to present your ideas

You may have your good ideas, but if you don't sell your ideas, no one will recognize their worth and consider you smart. So you need to learn how to present your ideas. Pronounce clearly, express your thoughts properly. And most importantly, let your enthusiasm (热情) about your ideas shine through. Enthusiasm spreads quickly. When you have something to say, say it well. Selling your ideas is not only good for your reputation (声誉), others can also benefit from your message.

Finally, you must also believe in yourself. Those who appear smarter than you simply have used the right tools to exercise their minds. You are smarter than you think.

1.When we practice self-critical thinking, we _________.

A. are very likely to doubt other people's ideas

B. are willing to believe and accept other people's ideas

C. can easily come up with better ideas than other people

D. can find weak points in our own ideas before other people

2.What can we learn from the passage?

A. Too many people think they can improve their intelligence.

B. Scientists can succeed much more easily than normal people.

C. Pronouncing clearly is the most important skill to express ideas.

D. Others can recognize the value of your ideas, if you sell them properly.

3.What does the passage mainly talk about?

A. How to be smart. B. How to argue forcefully

C. How to be successful D. How to do useful research