Now, let's take a look at these two sentences:

美味しい。
おいしい。
It's good [tasty].
Literally: "tasty / delicious."

美味しいです。
おいしい　です。
It is good [tasty].
Literally: "tasty / delicious + です."

What is the difference between these two sentences?

One of them has です.

OK. Thank you, Mr. Smarty Pants. What does that mean?

The version with です is more formal / polite.

Yes! Exactly.

Which leads me to my next question: How do we make these two sentences into questions?

That would be...

美味しい？
おいしい？
Is it good [tasty]?
Literally: "tasty / delicious?"

美味しいですか？
おいしい　です　か？
Is it good [tasty]?
Literally: "tasty / delicious + です + か?"

So, for casual sentences (i.e. the first sentence here), we can just end the phrase with a rising intonation to make it into a question. We occasionally do this in English, too: This is where I buy my ticket. This is where I buy my ticket?

美味しい。　→　美味しい？
It's good. → It's good?

Let's all take a moment to be thankful that we don't need to rearrange the word order for questions. That is, there isn't really a Japanese version of: Is this where I buy my ticket?

For formal / polite sentences (specifically, for sentences ending in です or in a verb in the masu-form, which we'll look at later), we add the particle か to the end of the phrase to make it into a question. In grammar textbooks, they probably won't use a question mark after the か, and they may even mention that a rising intonation is not needed. That said, many Japanese people will still use question marks after か and a rising intonation.

美味しいです。　→　美味しいですか？
It is good. → It is good?

The important thing to remember: か only* comes after です (or after ～ます for verbs).

*Well, not only, since we can sometimes put か at the end of very casual sentences. Doing so will require a high-level mastery of casual nuances, which we'll explore later in this course.

〇 ～？
〇 ～ですか。
〇 ～ですか？

△ ～か？
△ ～です？
△ ～ます？

Let's get into some exercises. Below, you'll find sentences that have already appeared in previous lessons. (If you can't understand any of these sentences, you should go back and review those lessons.)

Your task is to guess how to make the statements into questions.

(Note: Don't worry too much about how natural these sentences may be, since randomly turning statements into questions can result in some out-of-left-field questions. Instead, let's just focus on the process of forming questions from statements. We'll become masters of using the perfect sentences in given situations later in our studies.)

スタート！
Start!

Statement:
ピザは美味しい。
ピザ　は　おいしい。
Pizza is delicious.
Literally: "pizza + は + tasty / delicious."

Question:
ピザは美味しい？
ピザ　は　おいしい？
Is pizza delicious?
Literally: "pizza + は +tasty / delicious ?"

Statement:
ピザは美味しいです。
ピザ　は　おいしい　です。
Pizza is delicious.
Literally: "pizza + は + tasty / delicious + です."

Question:
ピザは美味しいですか？
ピザ　は　おいしい　です　か？
Is pizza delicious?
Literally: "pizza + は + tasty / delicious + です + か？"

Statement:
ビールは安い。
ビール　は　やすい。
Beer is cheap.
Literally: "beer + は + cheap."

Question:
ビールは安い？
ビール　は　やすい？
Is beer cheap?
Literally: "beer + は + cheap?"

Statement:
ビールは安いです。
ビール　は　やすい　です。
Beer is cheap.
Literally: "beer + は + cheap + です."

Question:
ビールは安いですか？
ビール　は　やすい　です　か？
Is beer cheap?
Literally: "beer + は + cheap + です + か？"

Statement:
綺麗な場所です。
きれいな　ばしょ　です。
It's a beautiful place.
Literally: "pretty + place + です."

Question:
綺麗な場所ですか？
きれいな　ばしょ　です　か？
Is it a beautiful place?
Literally: "pretty + place + です + か？"

Statement:
大変な仕事です。
たいへんな　しごと　です。
It's a tough job. // It's a difficult job.
Literally: "tough / difficult + job / work + です."

Question:
大変な仕事ですか？
たいへんな　しごと　です　か？
Is it a difficult job?
Literally: "tough / difficult + job / work + + です + か？"

Statement:
簡単な文です。
かんたんな　ぶん　です。
It's a simple/easy sentence.
Literally: "easy + sentence + です."

Question:
簡単な文ですか？
かんたんな　ぶん　です　か？
Is it a simple sentence? // Is it an easy sentence?
Literally: "easy + sentence + です + か？"

Statement:
簡単！
かんたん！
It's so easy!
Literally: "easy!"

Question:
簡単？
かんたん？
Is it easy?
Literally: "easy?"

Statement:
彼女の名前は春子です。
かのじょ　の　なまえ　は　はるこ　です。
Her name is Haruko.
Literally: "she + の + name + は + Haruko + です."

Question:
彼女の名前は春子ですか？
かのじょ　の　なまえ　は　はるこ　です　か？
Is her name Haruko?
Literally: "she + の + name + は + Haruko + です + か？"

Statement:
小学校の先生です。
しょうがっこう　の　せんせい　です。
I'm an elementary school teacher.
Literally: "elementary school + の + teacher + です."

Question:
小学校の先生ですか？
しょうがっこう　の　せんせい　です　か？
Are you an elementary school teacher?
Literally: "elementary school + の + teacher + です + か？"

Statement:
大丈夫。
だいじょうぶ。
I'm fine.
Literally: "OK."

Question:
大丈夫？
だいじょうぶ？
Are you all right?
Literally: "OK?"

That was a lot of examples! Props to you if you read through all of them.

In the coming Basics lessons, we'll look at making a wider variety of questions.