那时我已经从南京去北京上大学，每次返宁，都会看到后院的花木越来越茂盛茁壮。
B-Time I-Time B-Person O O O B-Location I-Location O B-Location I-Location O B-Organization I-Organization O O O O B-Location O O O O O B-Location I-Location O B-Thing I-Thing O O O O O O O O