で and も — Combining Two Sentences into One

After learning は〜です, you might write sentences like this:

父は医者です。母は主婦です。 → My father is a doctor. My mother is a homemaker.

Two sentences, two です — a bit repetitive. The Japanese solution: merge them into one.

Japanese has two merging methods — で (connective form) and も…も (parallel) — each suited to different situations.

Method 1: です → で (Connective Form)

This is the most versatile merging technique. Change the です in the first clause to で, then continue directly with the next clause:

A は X です。B は Y です。 ↓ A は X で、B は Y です。

で works like a comma + "and" in English — it means "I'll pause here, but there's more coming."

Examples

Before merging:

• 山田さんは日本人です。 Yamada is Japanese.
• 李さんは中国人です。 Li is Chinese.

After merging:

• 山田さんは日本人で、李さんは中国人です。
• → Yamada is Japanese, and Li is Chinese.

Only the last clause keeps です; everything before it becomes で.

Another example:

Before merging:

• 父は医者です。 My father is a doctor.
• 母は主婦です。 My mother is a homemaker.

After merging:

• 父は医者で、母は主婦です。
• → My father is a doctor, and my mother is a homemaker.

You can chain multiple clauses

で isn't limited to connecting just two clauses — you can keep going:

父は医者で、母は主婦で、兄は銀行員で、姉は看護婦です。 → My father is a doctor, my mother is a homemaker, my older brother is a bank employee, and my older sister is a nurse.

Only the very last clause ends with です; all preceding ones use で.

Same subject? Omit it

When two clauses share the same subject, the second one can drop it:

Before merging:

• 私はコンピューターの会社員です。 I'm a computer company employee.
• 私は今年は25歳です。 I'm 25 this year.

After merging:

• 私はコンピューターの会社員で、今年は25歳です。
• → I'm a computer company employee, and I'm 25 this year.

The second 私は is omitted because the subject hasn't changed.

Method 2: も…も (Both… and…)

When two items share the same predicate, you can use も…も to combine them:

A は X です。B は X です. (X is the same!) ↓ A も B も X です。

も replaces は, and 日本人です only needs to be written once.

Another example:

When to use で vs も…も

In short:

• Different endings → で (each clause says something different, just combined)
• Same ending → も…も (same thing applies to both, so say it once)

じゃありません: Casual negation

In conversation practice, you'll encounter じゃありません — it's simply the casual contraction of ではありません:

では is a bit of a mouthful, so Japanese speakers contract it to じゃ. The meaning is exactly the same:

私のじゃありません。 = 私のではありません。 → It's not mine.

Everyday conversation almost always uses じゃ; では is reserved for formal situations.

Putting it all together: Family introduction

Let's combine all these techniques in a full family introduction:

私の家族は5人家族です。父は医者で、母は主婦です。兄は銀行員で、姉は看護婦です。私はコンピューターの会社員で、今年は25歳です。

Translation:

My family has five members. My father is a doctor, and my mother is a homemaker. My older brother is a bank employee, and my older sister is a nurse. I'm a computer company employee, and I'm 25 this year.

Notice how only three です appear across five sentences — the rest are smoothly connected with で. Much more natural.

Summary

• です → で: The connective form — change です to で in earlier clauses. Only the final clause keeps です
• も…も: When two subjects share the same predicate, replace は with も and write the predicate once
• Use で when the predicates differ; use も…も when they're the same
• じゃありません is the casual version of ではありません — same meaning
• Self-introductions and family descriptions are where で appears most often

Practice

Q1. Combine these two sentences: "山田さんは先生です。李さんは学生です。"

Q2. Combine these two sentences: "これは私の本です。それは私の本です。"

Q3. What does 「父は医者で、母は主婦です。」 mean?