A ship in harbor is safe, but that’s not ______ ships are built for.
A.what | B.whom | C.why | D.when |
We couldn’t understand: what could ______ his sudden change of mind?
A.enjoy | B.explain | C.accept | D.mean |
I didn’t mean to break your vase—it was just ______.
A.an accident | B.an advantage | C.an agreement | D.an experience |
He was breathing ______ after the relay race.
A.heavily | B.slowly | C.carefully | D.weakly |
People are concerned about the quality of the air they ______.
A.hear | B.eat | C.drink | D.breathe |
She walked home by herself, ______ she knew that it was dangerous.
A.if | B.so that | C.although | D.because |