... 15 minutes isn't long enough to satisfy your interest.
15 minutes is followed by "isn't"
why we don't say "15 minutes aren't long wnough to satisfy your interest."
because "15 minutes" appears to be a subject
15 minutes actually is one amount or apriod of a time,
therefore we uses singular form of the verb.
Tip for today:
When we talk about a amount or meaturement, uses singular form of the verb.
1. Ten dollars isn't enough to pay for dinner.
2. Five liters of water is enough to wash the car.
例如：a piece of paper / five sheets of paper / two scraps of paper
one pile of papers on your desk
papers 另一個可數名詞的用法 → newspaper
push paper (片語) 表示作瑣碎的工作
purposefully (adv) 有決心地；有明確目標地
She purposefully told her father that she wants to pursue a career in music.
purposely (adv) 故意地
She purposely left her cell-phone at home so her boss wouldn't be able to reach her.
clutter (n) 凌亂；雜亂 // 當不可數名詞
My closet is full of clutter.
They took a whole day to clean up the clutter in the garage.
clutter (v) 弄亂；堆滿
His study room is cluttered with books and magazines.
steady (adj) 穩定的；平穩的
The steady increase of our sales proves that our strategies are correct.
The progress of his health condition has been slow but steady.
- Jun 18 Thu 2009 17:19