是...的

是...的 emphasizes specific information about a past action—typically when, where, how, or who.

Structure: Subject + 是 + Focus (time/place/manner) + Verb + 的

What it emphasizes:

• When: 我是去年來的 (I came last year)

• Where: 他是在北京學的 (He learned it in Beijing)

• How: 我們是走路去的 (We went on foot)

• Who: 這是誰做的？ (Who made this?)

Key points:

• 是 can be omitted, but 的 is essential

• The 的 usually comes at the end

• If there is an object, 的 can come before it: 我是在日本買的這本書

Not used for:

• Actions happening now

• Future actions

• General statements without emphasis