单选题：The reason why children learn their mother tongue so well li

题目内容：

The reason why children learn their mother tongue so well lies solely in their environment of learning, A．Right
B．Wrong
C．Not mentioned

参考答案：

答案解析：

Despite dangers and difficulties, the soldiers were resolute

Despite dangers and difficulties, the soldiers were resolute.A．uncomplaining B．u

分类：综合类题型：单选题

It took me a whole hour to solve the problem.A．work at B．work on C．work out D．wo

分类：综合类题型：单选题

本月生产产品400件，实际使用工时890小时，支付工资4 539元；直接人工的标准成本是10元/件，即每件产品标准工时为2小时，标准工资率为5元/小时。要求计算

分类：综合类题型：单选题

分类：综合类题型：单选题

因为投资的目的之一是为了获得利润，所以投资中心同时也必须是利润中心，可以分为自然的投资中心和人为的投资中心两种类型。（　　）

分类：综合类题型：单选题