Q1. What is the passage mainly about?

1. AHow to choose a good word book
2. BWhy learning similar new words together can cause confusion
3. CWhy fruits are healthy
4. DHow to travel to an airport

似た新しい単語を一緒に覚えると混ざりやすい、という内容が中心なので B。

Q2. How many students took part in the 2018 study?

1. A18
2. B48
3. C113
4. D133

133 Japanese university students learned English words とあるので D。

Q3. In this passage, "confuse" means ...

1. Aremember clearly
2. Bthink one thing is another thing
3. Cwrite neatly
4. Dlearn quickly

peach と pear を「取り違える」という意味なので B。confuse A with B「A を B と混同する」。

Q1. What did Tinkham find in 1993?

1. ARelated words were learned faster.
2. BUnrelated words were impossible to learn.
3. CRelated words and unrelated words were learned equally.
4. DRelated words took longer to learn.

sets of related words took longer to learn than sets of unrelated words とあるので D。

Q2. What did the 2018 study find?

1. ARelated words were learned in much smaller numbers.
2. BThere was no significant difference in the number learned, but related words caused more mix-ups.
3. CStudents made no errors at all.
4. DUnrelated words caused more mix-ups.

found no significant difference in the number of words learned. Even so, students made more mix-up errors with related words とあるので B。

Q3. Why are "frog," "green," "hop" and "pond" a good example for learners?

1. AThey are all names of animals.
2. BThey all have the same meaning.
3. CThey share a theme but are different kinds of words, so they are less likely to be confused.
4. DThey are the most difficult words in English.

which are different kinds of words とあり、テーマは共通でも品詞や意味が異なるので混ざりにくい。正解は C。

Q1. What is the main conclusion of the passage?

1. ASemantic sets are the best way to learn new words.
2. BSemantic clustering may not reduce total learning much but increases confusion.
3. CSpacing has no effect on vocabulary learning.
4. DJapanese learners cannot learn words in groups.

clustering may not cut much from how many words are learned, but it does add confusion とあるので B。

Q2. How did Nakata and Suzuki's study differ from earlier research?

1. AIt used only children.
2. BIt did not use Japanese learners.
3. CIt used artificial words only.
4. DIt controlled factors such as word properties that earlier studies had not separated.

They controlled for factors such as word properties, which earlier studies had not separated とあり、より厳密な点が違いなので D。

Q3. Why does the author call the spacing result "unexpected"?

1. AOne might expect spacing to help similar words most, but it helped unrelated words more.
2. BSpacing made learning worse for all words.
3. CSpacing was not tested in the study.
4. DSpacing helped only Turkish learners.

混ざりやすい関連語こそ分散が効きそうなのに、実際は helped unrelated words more than related ones だったため予想外だった。正解は A。