1.i used to spend all day with them, observing them and learning about their way of life. 我那时一整天都和它们待在一起,仔细地观察并了解它们的生活方式. 现在分词短语observing…of life作伴随状语. 1)used to表示过去常常做某事. 例句: i used to play football after school.过去我常常在放学后踢球. he used to live in the country.他曾经住在农村。
