If you can’t come tomorrow, we’ll____ have to hold the meeting next week.
There is no doubt _______ nearsightedness is a serious problem among the youth of our country.
You needn’t have ________ the speaker when he was speaking; there was enough time afterwards for you to ask questions.
It’s helpful to put students in a situation _______ they can learn how to cooperate with each other.
Lucy is a very optimistic girl. ______ she is faced with difficulties, she always sees the bright side.
All the people on the list must be told to attend the meeting; you must make sure that no one is _______.