Can you explain ________ the sun goes down in the west?
— Shall we make it next Saturday morning? — Sorry. I _______ a friend off at the airport then.
Many memories of old times were _______ by the conversation we had that evening.
— Tony, you seem in high spirits. — Yes. There is nothing _______ exciting than seeing my work in print.
He talks as if he knew the truth. _______, he knows nothing about it.
The sentence wants _______ once more as many students still have difficulty understanding it.