kenkyuu wa tsugi no dankai ni hairimashita.

topic particle

Breakdown of kenkyuu wa tsugi no dankai ni hairimashita.

• に: destination particle
• の: possessive case particle
• 入はいる: to enter

Questions & Answers about kenkyuu wa tsugi no dankai ni hairimashita.

Why is 研究 marked with は here? Could I use が instead?

は marks 研究 as the topic of the sentence, indicating we’re talking about “the research” in general. You could use が (研究が次の段階に入りました) to emphasize that it was the research (and not something else) that entered the next stage, but it makes the sentence feel more like new information or a sudden revelation. With は, you assume the listener already knows you’re talking about the research and you’re just giving an update.

What does the phrase 次の段階に入りました literally mean, and why is there a の between 次 and 段階?

• 次の段階 literally means “the next stage.”
• 次 means “next,” and when you want to turn it into an adjective modifying 段階, you add the genitive particle の. So 次の段階 = “the stage of next.”
• Then に入りました (“entered into”) completes the idea: “entered into the next stage.”

Why is に used before 入りました instead of another particle like を?

When you use 入る in the sense of “to enter into a state, period, or stage,” the thing you enter takes the particle に. So:
X に 入る = “to enter into X.”
Here, 次の段階 is X, so we say 次の段階に入りました. If you tried を入った, it would be ungrammatical because 入る is intransitive in this usage.

Why is the verb 入りました in the past tense? Isn’t the research still ongoing?