back-of-the-envelope

back-of-the-envelope envelope of the pulse back-of-an-envelope怎么翻译? Lincoln wrote the address on the back of a used envelope翻译 这句话什么意思? "The goodness of the bounding envelope " an envelope of pushing the envelope是什么意思 pushing the envelope push the envelope是什么意思 ride the back of Back of the sit at the back of the back