— Would you come to our party tomorrow, Della?— I’m afraid I can’t afford the time, but thank you for the invitation _______.

. John hadn’t been able to quit smoking at once; he had to control his smoking desire      .

---Thanks for your trouble. ---Not at all. I’m _____ pleased to help you.

Though it was in the midnight, ________ there were a lot of people in the street.

As is known to all language learners, the newly learnt words will soon be forgotten unless ______ used in everyday communication.