A hammer is useful when putting up a shelf.
Studying is useful if you want to get a good grade on a test.
You just did, didn't you? What if you just write a useful sentence?
The internet can be useful and harmful.
The inventor invented lots of useful things
Have you read the transcript? It was very useful.
I hate transform boundaries!!
I used the Socratic method to engage my students in a discussion about the history of philosophy.
A portable computer is very useful.
Shrewdness is useful in negotiating a business transaction.
I can give you several sentences.Learning how to use words properly is useful.You should make yourself useful and help your aunt sweep the floor.Speaking English is a useful skill.
My wristwatch has an altimeter, which as a backpacker, I find very useful.
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The detective gained useful information by following the trajectory of the bullet.