Learn Hardcore Japanese: bunpou no rensyuumondai ha kantan ni owarimasu. - Grammar practice exercises are easy to finish.

文法 = grammar
練習問題 = practice questions / exercises
文法の練習問題 = grammar practice questions / exercises
→ literally “practice questions of grammar”

So の is showing that the type or content of the 練習問題 is 文法.
Other similar patterns:

日本語の本 = a Japanese book / a book in Japanese
歴史の授業 = history class

What is the role of は in 文法の練習問題は?

は is the topic marker. It marks 文法の練習問題 as the thing the sentence is about.

So the basic structure is:

文法の練習問題は … = As for grammar practice questions, …
簡単に終わります。 = they finish / get finished easily.

In natural English, we usually drop the “as for” feeling and translate it as:

Grammar practice questions finish easily.
You can finish the grammar exercises easily.

The actual subject (like “they” or “I”) is not explicitly shown; は just sets the topic. Japanese often omits the subject when it’s clear from context.

Why is it 簡単に and not 簡単な or 簡単です?

簡単 is a na-adjective. To make it modify a verb (like an adverb in English), you usually add に:

簡単 → 簡単に = easily

Here it modifies 終わります (to end / to finish):

簡単に終わります = to finish easily / quickly / without much trouble

Compare:

簡単な問題 = an easy problem (adjective modifying a noun)
問題は簡単です。 = The problem is easy. (adjective as predicate)
問題は簡単に解けます。 = You can solve the problem easily. (adverb modifying a verb)

So:

簡単に終わります。 = It ends easily (adverb)
Not:
簡単な終わります。 (ungrammatical)
簡単です終わります。 (ungrammatical)

What exactly does 簡単に終わります mean? Is it “is easy to finish” or “finishes easily”?

Literally, 簡単に終わります is:

簡単に = easily
終わります = finishes / comes to an end (polite, non-past)

So it’s “(they) finish easily.”

In natural English, this often becomes:

They are easy to finish.
You can finish them easily.

Because English tends to express this idea as “be easy to V”, while Japanese is happy to say “V easily”.

So both:

The grammar exercises finish easily.
The grammar exercises are easy to finish.

are acceptable translations of 文法の練習問題は簡単に終わります。 depending on context.

What tense is 終わります? Does it mean “finish”, “will finish”, or “usually finish”?

終わります is the polite non-past form. In Japanese, non-past covers:

present (habitual / general truth)
future

The exact English tense depends on context:

Habitual:
- 文法の練習問題は簡単に終わります。
  → Grammar practice questions usually finish easily.
Future / prediction:
- もう少しですから、文法の練習問題は簡単に終わりますよ。
  → There’s not much left, so you’ll finish the grammar exercises easily.

So the Japanese form itself is neutral; context tells you if it’s “finish”, “will finish”, or “tend to finish” in English.

Who is actually doing the “finishing” in this sentence? Is the subject “I”, “you”, or “the exercises”?

Grammatically, 終わります here is intransitive: “(something) finishes / comes to an end.”

The most natural interpretation:

文法の練習問題 = the grammar practice questions
終わります = finish (themselves)

So, literally:

文法の練習問題は簡単に終わります。
→ As for grammar practice questions, they finish easily.

In real usage, this often implies:

You can finish the grammar exercises easily.
or
I can finish the grammar exercises easily.

Japanese doesn’t need to say “I” or “you” because the focus is on the exercises and their tendency to end easily. The subject (“I/you/we”) is understood from the situation, not from the grammar.

What is the difference between 終わります, 終えます, and 終わらせます?

These three verbs are related but have different grammar and nuance.

終わる (intransitive) → 終わります
- Meaning: to end / to be over / to finish (by itself)
- Subject is the thing that ends.
- 文法の練習問題は簡単に終わります。
  → The grammar exercises finish easily.
終える (transitive) → 終えます
- Meaning: to finish (something)
- You explicitly finish something as an action.
- 文法の練習問題を簡単に終えます。
  → I (can) finish the grammar exercises easily.
終わらせる (causative of 終わる) → 終わらせます
- Meaning: to make/let something finish → often used like “to finish (something)” as well, but with a slight nuance of causing it to end.
- 文法の練習問題をさっさと終わらせます。
  → I’ll hurry up and get these grammar exercises finished.

In your sentence, 終わります focuses on the exercises themselves (they end easily), not on someone actively finishing them.

Could you replace は with が in 文法の練習問題は簡単に終わります? How would it change?

Grammatically, you could say:

文法の練習問題が簡単に終わります。

The meaning changes subtly:

は → sets 文法の練習問題 as the topic (what we’re talking about in general).
- Often has a contrast or “as for X” feeling.
- As for grammar practice questions, they finish easily (compared to something else / in general).
が → marks 文法の練習問題 as the grammatical subject, often presenting new or important information.
- It’s the grammar exercises that finish easily. (emphasis on them, maybe in contrast to other things)

In many beginner contexts, は sounds more natural here because you’re making a general statement about grammar exercises.

Why is the word order 文法の練習問題は簡単に終わります? Could I move 簡単に?

Basic order:

[topic] は [manner] [verb]
文法の練習問題は簡単に終わります。

You can move 簡単に somewhat freely, but you must keep the verb at the end:

文法の練習問題は簡単に終わります。 (most natural)
文法の練習問題は結構簡単に終わります。 (adds 結構, still natural)
簡単に文法の練習問題は終わります。 (possible, but sounds more marked; might emphasize “easily”)

You cannot break up the verb or put 終わります in the middle:

✕ 文法の練習問題は終わります簡単に。 (wrong in Japanese)

General rule: adverbs like 簡単に, 早く, よく go before the verb they modify.

What exactly does 練習問題 mean? How is it different from just 練習 or 問題?

練習 = practice (the activity of practicing)
問題 = problem / question / exercise (like in a textbook)
練習問題 = practice problems / practice questions / exercises

So:

文法の練習 = grammar practice (the act of practicing grammar)
文法の問題 = grammar questions / problems (could be test questions)
文法の練習問題 = grammar practice exercises (questions you do to practice)

In textbooks, 練習問題 usually refers to the numbered questions or exercises you work through to practice what you learned.

Why is the verb in ます-form (終わります) instead of the dictionary form 終わる?

終わります is the polite form of 終わる.

終わる = plain / dictionary form
終わります = polite -ます form

You use 終わります when:

speaking politely to teachers, classmates you’re not close to, co‑workers, etc.
writing in textbooks, explanations, and most formal materials.

If you were speaking casually to a close friend, you might say:

文法の練習問題は簡単に終わる。

Same meaning, but less formal.