Hello there, English learner! 👋
Awesome question about “which” and “that.” These two words can be tricky because they both introduce clauses that describe nouns—but they aren’t always interchangeable. The difference mainly comes down to meaning and comma usage in a sentence. Let’s break it down step by step!

🗝️ Quick Summary

Let’s explore what that all means. 👇

📚 1. “That” – Restrictive Clause (Essential Information)

✅ Use “that” when the information is necessary to understand what you’re talking about.

🧠 It defines or limits the noun.

🗣️ Examples:

• The cookies that she baked were delicious.
  → (Only those cookies—not all cookies—were delicious.)
• The car that is parked outside belongs to Jake.
  → (Not just any car—that specific one.)

❌ No comma before “that.”

📚 2. “Which” – Non-Restrictive Clause (Extra Information)

✅ Use “which” when the information is extra—it’s not needed to identify the noun.

🧠 It adds detail, but the sentence still makes sense without it.

🗣️ Examples:

• The cookies, which she baked this morning, were delicious.
  → (You already know which cookies—we’re just adding extra info.)
• His car, which is red, is parked outside.
  → (We already know which car. “Which is red” is just extra.)

✅ You must use a comma before “which.”

🔁 Side-by-Side Comparison

❗ So Why Does It Matter?

Using “that” vs. “which” tells your reader:

• Whether the information is crucial to the meaning, or
• Just additional detail

Changing from one to the other can change the meaning of the sentence!

📝 Practice: Choose that or which

1. The shoes _____ I bought yesterday are already dirty.
2. My laptop, _____ is three years old, still works fine.
3. The teacher assigned the book _____ everyone must read.
4. His dog, _____ is very friendly, barked at the mailman.
5. The street _____ we turned on was closed.

✅ Answers:

1. that (essential info: which shoes?)
2. which (extra info: laptop still works)
3. that (essential info: specific book)
4. which (extra info: more about the dog)
5. that (essential info: which street?)

💡 Learning Tip:

Pro Tip:

• If the sentence needs the clause to make sense → use “that” (no comma).
• If the clause is just extra info → use “which” (with commas).

🎯 Trick to remember:

✏️ That = Tight to the sentence (no commas)
✏️ Which = Wrapped in commas (extra info)