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Xiao Ming said, "If I don't know, Xiao Hong definitely doesn't know", which is equivalent to its inverse negative proposition "If Xiao Hong knows, then Xiao Ming also knows". For Red to be able to tell the entire date at the beginning, only the n she knows is unique among the 10 groups. Looking at the array, it is not difficult to see that only 7 on June 7 and 2 on December 2 are unique.

Then "if Red knows, then Ming knows" means that m is 6 or 12, because only then, when Red first says she knows, Ming can deduce the entire date from what he knows m.

After listening to Xiao Ming's words, Xiaohong said, "I didn't know it originally, but now I know", that is, in fact, Xiaohong can't make a judgment at the beginning, so N is not unique. m is 6 or 12 and n is not unique, and there are only three dates: June 4, December 1, and December 8.

Obviously, each of the three dates is unique, so it's not surprising that Xiaohong can judge.

In the end, Xiao Ming said, "Oh, then I know too", that is, among the above three dates, Xiao Ming's grasp of M must be unique, otherwise he will not be able to judge. Only 6 on June 4 is unique, so the teacher's birthday is June 4.

Note: The first step of the derivation of the upstairs students is wrong, and the equivalent deformation of Xiao Ming's words should be made before derivation.

1.Xiao Ming said: If I don't know, Xiaohong definitely doesn't know.

This sentence excludes June and December, because if m is 6, n may be 7, and the birthday can only be June 7, then Xiao Ming can't be sure that Xiao Hong doesn't know, and similarly, if M is 12, n may be 2, Xiao Ming can't be sure.

2.Xiaohong said: I didn't know it at first, but now I know.

This sentence excludes March 5 and September 5, because n is 5, and Xiaohong can't be sure which day.

3.Xiao Ming said: Oh, then I know too.

Now there are March 4, March 8, September 1

If M is 3, then Tom can't be sure if it's March 4 or March 8, so M can only be 9 and the birthday is September 1.

September 1 The inference process is very verbose, and only two points are mentioned: 1You, you, me, and I are too verbose, and replace them with m and n instead of the original words;

2.Build one.

Use methods to simplify the inference process.

1. The distance between P1 and P2 is.

c-30=102-30=72

2: The area of the green side is.

e*b-semicircle-trapezoid=

3: The model volume is.

b-d）*30*64-30*

e*c*(b-d)-trapezoidal-round branch good column.

The total volume is.

It's very simple, just write the chemical formula on the first line, and write the corresponding name on the second line. Anyway, he gave you the ion symbol.

So much, let's connect with the beginning of the school.

Analysis: 2)2Al+6HCl==2ALCl3+3H2;

3) Solution: Let the mass of al2o3 be x.

al2o3+6hcl==2alcl3+3h2ox

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