BBC在线收听下载:英国警方称已逮捕曼彻斯特袭击大部分嫌疑人

短语讲解：

1.At least 28 Coptic Christians were killed when their bus was ambushed on thier traveling to a monastery.

at least 至少
例句：He's been away for at least a week.
他走了总有一个星期吧。