在托福阅读备考中，想要快速的提升自己的托福阅读能力，除了不断的累积自己的词汇和句型之外，从TPO练习入手也不失为一个不错的方法。那么，在以下内容中我们就为大家带来TPO7托福阅读词汇，希望能为大家托福阅读备考带来帮助。
Paragraph 1: Photographic evidence suggests that liquid water once existed in great quantity on the surface of Mars. Two types of flow features are seen: runoff channels and outflow channels. Runoff channels are found in the southern highlands. These flow features are extensive systems—sometimes hundreds of kilometers in total length—of interconnecting, twisting channels that seem to merge into larger, wider channels. They bear a strong resemblance to river systems on Earth, and geologists think that they are dried-up beds of long-gone rivers that once carried rainfall on Mars from the mountains down into the valleys. Runoff channels on Mars speak of a time 4 billion years ago (the age of the Martian highlands), when the atmosphere was thicker, the surface warmer, and liquid water widespread. 【TPO8- Running Water on Mars?】
1. The word “merge” in the passage is closest in meaning to
○ expand
○ separate
○ straighten out
○ combine
答案： (4)
