下列实验现象叙述正确的是(   )

某车间有56名工人，每人每天能生产螺栓16个或螺母24个，设有x名工人生产螺栓，y名工人生产螺母，每天生产的螺栓和螺母按1：2配套，下面所列方程组正确的是（　　）

    Hi, I am Susan. I am from the U. K. But now I'm studying(学习) in China. I'm going to do many things in the winter holiday. First, I'm going to finish my homework. Then I'm going to take a trip. I'm going to Beijing. It's snowy in Beijing. There is white snow everywhere. So I'm going to make a snowman. I can ski. My parents will come to China with me. We are going to fly there. We are going to have a nice trip.

根据短文内容判断正误。

有学者认为“抗日战争改变了中国反侵略斗争屡败的局面”，对此理解错误的是（    ）