它們的th發音是不同的，前面的birthday的th發清子音，後面的that的th發濁子音。

birthday/ˈbɜːθdeɪ/裡面的th發/θ/音。

Gifts and messages snowed in on her birthday .
她生日時，禮物和賀詞紛紛而來。

Have you chosen what you want for your birthday ?
你過生日要什麼東西決定了嗎？

She received many birthday tokens .
她接到了許多生日禮物。

His graduation day concurred with his birthday .
他畢業典禮的日子與生日同一天。

She was shy two months of her nineteen birthday .
她差兩個月就是十九歲的生日。

The little boys were swimming in their birthday suits .
那群小孩在光著屁股游泳。

Today is the child 's first birthday .
今天孩子滿週歲。

She sent me a birthday card with a heart on it .
她送一張有心形圖案的生日卡給我。

I congratulate you on your birthday .
我慶祝你的生日。