母亲当时没有经济收入，姐姐在黑大哲学系读书，靠每月18元的助学金生活。
B-Person I-Person B-Time I-Time O O O O O O O B-Person I-Person O B-Organization I-Organization I-Organization I-Organization I-Organization O O O O B-Time I-Time B-Metric I-Metric I-Metric O B-Thing I-Thing I-Thing O O O