— Where does your mother work?
— She works a farm. She is a farmer.
A:on
B:in
C:at
D:to
截止2013年底,中国高速铁路营运里程达到11000km,居世界首位,将11000用科学记数法表示为____.
____ (luck), he didn't pass all the exams.
8×7×3×125=____
一个两位数从右边起第一位是____位,第二位是____位.
读“大洲大洋图”,将地理事物的名称填在横线上.
大洲:①____、②____、③____、④____、⑤____、⑥____、⑦____
大洋:A____、B____、C____、D____.