“构造法”奉反例在立体几何教学中的运用杨广才要证明一个数学命题正确，必须对命题所包含的所有可能情况及类型予以证明，切忌特殊代替一般。不然，证明不严密，所得结论不一定普遍成立。但对一个命题推证其不成立，只要举一个反例即可。这时的要求与前者恰恰相反：越特... The use of “construction method” in the teaching of solid geometry teaching Yang Guangcai has to prove that a mathematical proposition is correct and must prove all possible situations and types involved in the proposition, and avoid special substitution. Otherwise, the proof is not strict, and the conclusions obtained may not be universally established. But arguing that it is not true for a proposition, just give a counterexample. The request at this time is the opposite of the former: the more special...