1, if the answer has a root sign, don't choose.

2. If the answer is 1, please select.

3. When all three answers are yes, choose the right one.

4. When one is positive X and the other is negative X, choose one of them.

The question looks simple, so the answer is complicated, and vice versa.

6. What to choose in the previous question and what to choose in this question, if three identical ones appear in succession, it is not suitable for this article.

7. Whether the answer to the question is good or not depends on the eyes.

8. When none of the above is feasible, choose B. ..

Second, math multiple-choice skills

1. Choose to fill in the blanks for the questions with inequality, choose the special value method, bring in the middle value, and choose the ones that are easy to get;

2. If transcendental expressions appear in equations or inequalities, give priority to the thinking method of combining numbers and shapes, and keep in mind various functional models and the characteristics of each model; 3, the topic of function or equation or inequality, first think directly and then establish the relationship between the three. Consider the domain first, and then use the "three-in-one theorem". The zero point of the function is the root of the equation.

4. In the face of elementary functions with parameters, we should grasp the invariance of the parameters when learning. Such as constant fixed point, symmetry axis of quadratic function, period of trigonometric function, etc.

5. The problem of constant establishment or its opposite can be transformed into a maximum problem. Pay attention to the application of quadratic function, flexibly use the maximum value on the closed interval, and discuss it in categories, which should not be repeated or omitted;

6. To find the value range of parameters, we should establish an equation or inequality about parameters, complete or solve the inequality with the definition domain or value domain of the function, take the separation constant, and finally become a constant establishment problem to find the maximum value;