新生儿期指从出生脐带结扎至生后：（ ）
A．7天
B．14天
C．28天
D．30天
E．60天
参考答案：C
Frank left school at 16, he still became a successful writer.
A．Ever since
B．In fact
C．After all
D．Even though
简述下火放炮的原因？
