短文改错（共10小题；每小题1分，满分10分）

短文中共有10处语言错误。错误涉及到添加、删除或修改。

添加：在缺词处加符号Λ，并在其下面写出该加的词。删除：把多余的词用／划掉

修改：在错词下面划个横线，并在该词下面写出修改后的词。

Attention please, everyone!

About 50 students from American will come to our school for the visit on October 4th,

Sunday. Our class will greet them. We will meet at the school gate at 8:40 am and giving them a

warm welcome. They will arrive at 9:00 am, and then we will show the American students to the

schoolyard, the lab building or the teaching building. There will have a friendly basketball game

on the playground at 10:00. we will leave our schools at 11:00. We should polite to our guests

and talk with them in the English.

That’s all. Thank you.

甲粮油贸易公司与乙食用油脂厂签订一份合同，双方约定由甲方提供毛糖油10吨，乙方负责加工成精糖油。乙方应以甲方提供的毛糖油酸价为基数，降低8个酸价，并脱色去杂，使其达到食用标准，加工费由甲方提货时付清。合同签订后，乙方就甲方提供的毛糖油按约定降低8个酸价处理。后甲方在提取精糖油时，经化验发现其高于食用标准2个酸价，当即要求乙方返工。双方对返工费的负担发生争议。根据上述案情，请回答下列问题：

甲乙所订合同属何性质的合同

A．买卖合同

B．委托合同

C．承揽合同

D．承揽和买卖的混合合同