You should study in an efficient manner. ✬

The English language is undoubtedly the easiest and at the same time the most efficient means of international communication. ✬

Which air conditioner do you think is the most efficient? ✬

A calculator is more efficient than an abacus. ✬

We're efficient. ✬

You're efficient. ✬

Tom is efficient. ✬

I'm efficient. ✬

You're so efficient. ✬

You're very efficient. ✬