day by day和day after day的区别

例句：Day by day his condition improved.他的健康状况一天天好转。Day by day I am getting better and better。我在一天天地好转。I live for the moment, day by day, not for the past.我活在当下，过一天算一天，而不是活在过去。I waited for news, day after day, expecting to hear.我日复一日地等着，期待能听到消息。