单项选择题
[听力原文] M: Nancy, why were you late for class this morning W: I overslept and missed the bus.
A．She got up late than usual. B．She forgot her class. C．Her clock was half an hour slow. D．The bus was late.
A．with B．on C．for D．in
A．D)100 the population of the earth was about ______.A) 800 thousand B．1 million C．250 million D．500 million