Think back to the first thing you remember. Chances are, you were at least a couple of years old when those events happened. Children under three are very aware of the world around them and they do seem to remember things from the recent past. Yet, one day, those early memories are gone.

Between us and our earliest experiences lies a mysterious barrier. Interestingly, this is not just true for humans. Experiments show that mice also forget their early learning. Young mice that learn to fear a place where they received a shock do not recognize it after they grow up. Scientists who study this phenomenon, known as childhood amnesia (遗忘), have made surprising discoveries about how this forgetting works.

So, are the memories gone, or are they just out of reach? Some research suggests that in mice, those memories still exist. In one study, researchers marked the brain cells that were active when young mice learned to fear a certain space. Months later, when the grown mice had forgotten this fear, the scientists reactivated those same cells. Suddenly, the mice reacted as if they remembered the fear. This finding suggests that, at least in some forms, early memories are not effaced — they may simply become inaccessible.

What about humans? Scientists at Yale University have managed to scan the brains of young children. They found that kids as young as one year old do form memories in a way similar to adults. This hints that humans, too, may create early memories that later cannot be reached. One researcher notes that while talking about past events or showing photos can help a child remember, the pure memory that is not discussed will soon fade away.

Why do we forget our early years? It remains a mystery. But perhaps the value of early memories is not in the specific details we lose, but in how they help us build a general understanding of the world. Such knowledge stays with us and helps us make decisions, even if we cannot recall the individual moments themselves.

1.1.Why does the author mention the mouse experiment in Paragraph 2?

A To prove fear is easily learned.

B To show amnesia is cross-species.

C To show memory loss is permanent.

D To compare memory of different animals.

解析：选B。B推理判断题。作者在第二段先指出人类早期记忆存在屏障，紧接着说“this is not just true for humans”，随后用小鼠实验证明它们也会忘记早期学习，可见写作意图是说明童年遗忘是跨物种存在的现象。故选B。

2.2.The underlined word “effaced” in Paragraph 3 most probably means ________.

A completely wiped out

B secretly stored away

C gradually disappearing

D automatically recovered

解析：选A。A词义猜测题。第三段开头提出核心问题：记忆是消失了（gone），还是仅仅无法触及（out of reach）？随后实验证明通过激活神经元可以让成年老鼠重新表现出恐惧反应，因此结论是早期记忆并没有被“effaced”，而只是变得“inaccessible”。既然记忆只是无法获取而非真正消失，那么“effaced”应对应前文的“gone”，意为“被彻底抹去”。故选A。

3.3.What can be inferred from the Yale University study?

A Brain scans can recover lost memories.

B One-year-olds have better memory than adults.

C The way babies form memories is like that of adults.

D Memories formed in babies are always discussed later.

解析：选C。C推理判断题。第四段明确写道：“They found that kids as young as one year old do form memories in a way similar to adults.”由此可知，婴儿形成记忆的方式与成年人相似。故选C。

4.4.What is the author’s attitude toward early childhood amnesia?

A It is a problem to be solved.

B It may have a positive function.

C It causes great concern.

D It is entirely without value.

解析：选B。B观点态度题。最后一段作者指出：早期记忆的价值“is not in the specific details we lose, but in how they help us build a general understanding of the world”，并且这种理解“stays with us and helps us make decisions”，说明作者认为童年遗忘可能有其积极功能。故选B。