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数算练习告诉我们算术运算的原理,而不是单单的记忆和不断演算。
The dinosaurs became extinct because they didn't have a space program. And if we become extinct because we don't have a space program, it'll serve us right!
生活中最大的荣耀不在于从不跌倒,而在于每次跌倒后都能站起来。