题目内容：

用since和for填空
i’ve been here------two years i’ve been here------ yesterday i’ve been here-------i was a child
i’ve been here-------two years ago
he’s been in class --------4 o’clock
he’s been in class --------an hour ago
he’s been in class --------4 hours
they’ve lived in new york-------she left here
they’ve lived in new york-------1999
they’ve lived in new york-------last month