自由之树需要经常用爱国者和暴君的鲜血来浇灌。
The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants.
粮食安全始于土壤安全。
The best way to learn mathematics is to do mathematics.
我们必须重视儿童心理发展期间的生理活动与动作。