— John has put forward ______ most challenging question for us to answer.— Yes, it really is. I have never heard ______ harder one.
. Research findings show we spend about two hours dreaming every night, no matter what we ____ have done during the day.
.I felt sure that __________qualification, ability and experience, you are suited to the position we have in mind.
---Are you happy with this laboratory? ---Not a little. We can’t have__________.
.Friends are like leaves, __________everywhere, but true friends are like diamonds, precious and rare.
.When__________a new word, you’d better__________a dictionary.