题目

阅读理解Next month, I'm traveling to a remote area of Central Africa and my aim is to know enough Lingala—one of the local languages—to have a conversation. I wasn't sure how I was going to manage this—until I discovered a way to learn all the vocabulary I'm going to need. Thanks to Memrise, the application I'm using, it feels just like a game.People often stop learning things because they feel they're not making progress or because it all feels like too much hard work， says Ed Cooke, one of the people who created Memrise. We're trying to create a form of learning experience that i(绵阳)如图所示，宽为50cm的矩形图案由10个全等的小长方形拼成，其中一个小长方形的面积为 [　　] A．400B．500C．600D．4000