Practise the thinking. Keep the judgement.
JLPT N3 grammar in reading: follow the relationship between ideas
Use reasons, contrasts and references to explain a short passage before choosing a grammar answer.
What should you identify before translating?
Name the relationship between the ideas: reason, result, contrast, condition or sequence. These relationships constrain what a sentence can mean even when one noun is unfamiliar.
Read the sentence before and after a gap. A grammar choice can be locally well formed and still contradict the writer’s point. Keep a brief account of the whole passage beside the individual sentence.
A contrast can change the conclusion
この店は駅から遠いです。しかし、毎日たくさんの人が来ます。The shop is far from the station, yet many people come every day. しかし signals a contrast between the inconvenient location and the attendance.
Replacing しかし with そのため would present the distance as the reason people come. That is not the relationship established by the original passage. It could work with more explanation, but you should not invent that missing explanation.
Follow what a short reference points to
In この店は安くて便利です。そのため、よく利用します。, そのため refers back to the stated advantages. Read it as a link to the preceding reason, not as a new object in the shop.
Underline the actual words supporting the relationship. If your explanation depends on a fact absent from the passage, separate that assumption from the text. This is particularly useful when two options both sound plausible.
Review the missed relationship, then change the passage
Write a one-line summary of each sentence and connect the lines with “because”, “but” or “if”. Then return to the Japanese connector. You are checking meaning before rehearsing the form.
For a new attempt, change the location or outcome while keeping the relationship. Later, deliberately change the relationship as well. This gives you two different checks rather than repeated exposure to one answer.
Try it yourself
雨が降っています。＿＿、試合は予定どおり行います。Which relationship fits: result or contrast?
Show the answer and explanation
Contrast: しかし is one possible connector.
The second sentence says the match proceeds despite the rain. The practice checks the relationship, not a claim that only one Japanese expression could ever fit.