wèi shén me
为什么群众这么爱护解放军？因为解放军是人民的子弟兵
Wèishénme qúnzhòng zhème àihù jiěfàngjūn? Yīnwèi jiěfàngjūn shì rénmín de zǐdìbīng.
Why do the masses love and care for the People's Liberation Army so much? Because the PLA are the people's own soldiers.
他这么做到底是为什么？注意“为什么不”常含有劝告的意思，跟“何不”相近，如：这种技术很有用处，你为什么不学一学？
Tā zhème zuò dàodǐ shì wèishénme? Zhùyì 'wèishénme bù' cháng hányǒu quàngào de yìsi, gēn 'hébù' xiāngjìn, rú: Zhè zhǒng jìshù hěn yǒu yòngchu, nǐ wèishénme bù xué yī xué?
Why exactly does he do this? Note that 'why not' often contains the meaning of advice, similar to 'why don't you', for example: This technology is very useful, why don't you learn it?