The more one is _______ the English-speaking environment, the better he or she will learn the language.

It was not until she got home ______ Jennifer realized she had lost her keys.

.Our boss suggested we clerks ______ good sales methods and his words suggested that ______ did the best ______ the best prize.

 Modern science has given ____clear evidence ____ smoking can lead to many diseases ____ it’s time for us to take measures.

 ________ doesn’t seem to have been much difficulty in solving the problem.