| For his homework, Thomas had to write words on cards and connect them with rubber bands.托马斯的家庭作业是把单词写在卡片上，然后用橡皮筋把它们连起来。
The teacher told him to connect any two words that differ by exactly one letter.老师让他把仅相差一个字母的任意两个单词连接起来。 Thomas did this, as you can see in the picture on the right.托马斯就是这样做的，如您在右边的图片中所见。 When Thomas returned from having a break he got a surprise.托马斯休息回来时吃了一惊。 Peter, his little brother, had erased all the words!彼得,他的小弟弟把所有的字都擦掉了！ |
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Also, the cards were completely mixed up, as you can see in the image on the left.而且，正如您在左边的图片中所看到的那样，这些卡片完全被打乱了。
Importantly, the rubber bands still connected them as before.重要的是，橡皮筋仍像之前那样把它们连在一起。 Thomas was sure he could put the words back in the correct place.托马斯确信他能把那些词放回正确的位置。 |
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Question: 问题:
Which of the pictures below contains the words in exactly the right places?
下面哪张图片中的单词位置完全正确？
A.
B.
C.
D.
Explanation 解释
The correct answer is: 正确答案是：
We can proceed by counting the edges going from each node. There are 2 nodes with 3 edges, 2 nodes have two edges and 2 nodes have 1 edge. There is only one node with one edge connected to a node that has two edges. So we have identified the node for “EAR” and “CAR”. We can continue with this method.
我们可以从计算每个节点的出边数量开始。有 2 个节点有 3 条边，2 个节点有 2 条边，还有 2 个节点有 1 条边。只有一个节点有 1 条边，且这条边连接到一个有 2 条边的节点。这样我们就确定了“EAR”和“CAR”对应的节点。我们可以继续用这种方法。
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