单选题 Working memory, or short-term memory, involves the ability to hold and use information in the immediate future. 21 is only held in working memory for about 20 seconds. The challenge that students 22 is to move information from their working memories into their long-term memories. If they don"t do this in about the first few minutes after receiving the information, that information can be lost. To keep this newly learned material from 23 away, it needs to enter the network of the brain"s wiring.
After repeated practice, working memories are set down as permanent neuronal (神经的) circuits 24 to be activated (激活) when the information is needed. When a memory has been recalled 25 its neuronal circuits are more highly developed because of their repeated activation.
26 exercising a muscle, these circuits then become more efficient and easier to access and activate. Practice results 27 repeated stimulation of the memory circuit. Like hikers along a path 28 eventually leave a depression in the road, repeated practice stimulates cells in the memory circuit such that the circuit is reinforced and becomes 29 . This means it can be quickly turned from off to on, and switched 30 through a variety of cues coming in from the senses.

【正确答案】 B

【答案解析】[解析] 本题应该注意上下文的线索。由于前后两个句子中都有“information”一词出现，而其他选项的词汇在上下文中找不到支持线索，意思也不符合语境。

【正确答案】 C

【答案解析】[解析] 由于空格前面是一个一般动词，后面只能使用一个程度副词，所以C项是最佳答案。此外，这是一个时间句，前面已经有了一个时间词“when”，后面就不用其他选项时间词了。

【正确答案】 A

【答案解析】[解析] 注意固定搭配词组“result in”意思为“导致，引起”，原因在前结果在后。而“result from”意思为“由……导致”，结果在前原因在后。“result”一词与B和D项的介词没有搭配。

【正确答案】 D

【答案解析】[解析] 本题为语法题。应该注意动词“leave”词尾没有加“s”，后面的从句是复数名词“hikers”的定语从句，所以引导词应该是“who”。其他选项都不符合语法要求。